Sorry for being a lit late, but here is the post
Passimian

No going to talk a lot about this guy, because I didn´t save any replay using this guy :c.
I tried to run 3 different sets, to go out of the standar Scarf Set.
As I said, Im not going to talk a lot about passimian, as I didn´t save any replay, but I would suggest that Scarf is the only viable set, CB hits decent chunck, however, most of the time I was in troubles on speed ties against Gardevoir and Chandelure, or be rk by Cobalion or Noivern. Sub Bulk Up looked so meme, and didn´t give me good results, 100 Base hp is good, however Infiltrator Noivern ignores Sub and KO with Hurricane or Draco Meteor after some chip, also this set doesnt enjoy Hyper Voice from Sylveon, and can't KO Toxtricity.
Teams that I used: https://pokepast.es/208c5ffb70ab0147
Sigilyph

I have 4 replays with this guy, as u will see, the teams that I faced on ladder are very different :)
Ok, Sigilyph gave me decent resulst, most standar set is 3 attacks + Roost with LO, and I had to run Modest Nature instead of Timid, because Timid Sigilyph does a shit damage, just want to show some calcs to compare Timid and Modest.
I decided to run Energy Ball instead of Air Slash, as it allows to lure on Bulky Water and Rock types checks, Sigilyph obviusly has a hard time dealing with Incineroar, as it is a Psychic type that lacks on Fighting Coverage or a strong second Stab, air Slash is ok, 3HKO Incineroar, however I feel like Energy ball covers more than Air Slash does.
The second set was more meme, however it was useful, Sigilyph invites Incineroar, water and rock types to come, so trick them an Sticky Barb helps to annoy, Incineroar will lose some health any time it comes, and get ride of HDB make it even more weak to chip damage, bulky waters hates dont have Leftovers, and Sigilyph can abuse them by setting up Calm Mind and ignores Toxic thanks to Magic Guard, this also works on some mons that are not as common as they used to be, but can check Sigilyph, like Umbreon.
Teams that I used: https://pokepast.es/2a74b29bcfeae1b3
On LO Sigilyph team, I decided to build a Kind of Para Spam, using Stun Spore Roserade, because Sigilyph really needs that Speed Control to outspeed stuffs like Noivern and Cobalion, and still dealing a decent damage with Modest Nature.
To conclude, I would suggest don´t use Passimian without Choice Scarf, as it needs a lot of support to use more offensive sets.
Sigilyph is an interesting pick, however it does little damage and need some hazard support to become a treat, and that is difficult considering that UU is a metagame where HDB is a common item, also Sigilyph is outclased by other Psychic types, examples are Gardevoir that hits harder with Specs and has a second good Stab on Fairy type. Reuniclus has a even higther SpAtk, and also can run Recovery + 3 Attacks with LO, both of them have basically the same checks as Sigilyph, but those checks have a difficult time trying to switch in on Gardevoir and Reuniclus than Sigilyph.
Passimian

No going to talk a lot about this guy, because I didn´t save any replay using this guy :c.
I tried to run 3 different sets, to go out of the standar Scarf Set.
Passimian @ Choice Scarf
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Close Combat
- Knock Off
- U-turn
- Iron Head
Passimian @ Choice Band
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Close Combat
- Knock Off
- U-turn
- Iron Head
Passimian @ Leftovers
Ability: Defiant
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Substitute
- Bulk Up
- Drain Punch
- Iron Head
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Close Combat
- Knock Off
- U-turn
- Iron Head
Passimian @ Choice Band
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Close Combat
- Knock Off
- U-turn
- Iron Head
Passimian @ Leftovers
Ability: Defiant
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Substitute
- Bulk Up
- Drain Punch
- Iron Head
Teams that I used: https://pokepast.es/208c5ffb70ab0147
Sigilyph

I have 4 replays with this guy, as u will see, the teams that I faced on ladder are very different :)
Sigilyph @ Life Orb
Ability: Magic Guard
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Psychic
- Heat Wave
- Energy Ball
- Roost
Sigilyph @ Sticky Barb
Ability: Magic Guard
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Trick
- Calm Mind
- Roost
- Psychic
Ability: Magic Guard
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Psychic
- Heat Wave
- Energy Ball
- Roost
Sigilyph @ Sticky Barb
Ability: Magic Guard
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Trick
- Calm Mind
- Roost
- Psychic
https://replay.pokemonshowdown.com/gen8uu-1092292835
https://replay.pokemonshowdown.com/gen8uu-1092580230-9gf1ybcetqnph2ody9h0o14y94pyhkepw
https://replay.pokemonshowdown.com/gen8uu-1092593965-1nc97p7xd7uefg7po5sh56d8t4xxjecpw
https://replay.pokemonshowdown.com/gen8uu-1092599328-9p8a2c1gy180wn3w049h3pmw7i88id0pw
Opposing teams were so different :) Pls ban Drought
https://replay.pokemonshowdown.com/gen8uu-1092580230-9gf1ybcetqnph2ody9h0o14y94pyhkepw
https://replay.pokemonshowdown.com/gen8uu-1092593965-1nc97p7xd7uefg7po5sh56d8t4xxjecpw
https://replay.pokemonshowdown.com/gen8uu-1092599328-9p8a2c1gy180wn3w049h3pmw7i88id0pw
Opposing teams were so different :) Pls ban Drought
Timid Sigilyph
252 SpA Life Orb Sigilyph Energy Ball vs. 252 HP / 252+ SpD Gigalith in Sand: 122-146 (32.6 - 39%) -- 5.2% chance to 3HKO after Leftovers recovery
252 SpA Life Orb Sigilyph Heat Wave vs. 252 HP / 252+ SpD Bronzong: 148-177 (43.7 - 52.3%) -- guaranteed 3HKO after Leftovers recovery
252 SpA Life Orb Sigilyph Energy Ball vs. 240 HP / 252 SpD Solid Rock Rhyperior: 370-437 (85.8 - 101.3%) -- 6.3% chance to OHKO after Leftovers recovery
252 SpA Life Orb Sigilyph Psychic vs. 252 HP / 4 SpD Sylveon: 130-153 (32.9 - 38.8%) -- 8% chance to 3HKO after Leftovers recovery
Modest Sigilyph
252+ SpA Life Orb Sigilyph Energy Ball vs. 252 HP / 252+ SpD Gigalith in Sand: 133-159 (35.5 - 42.5%) -- 89.2% chance to 3HKO after Leftovers recovery
252+ SpA Life Orb Sigilyph Heat Wave vs. 252 HP / 252+ SpD Bronzong: 164-195 (48.5 - 57.6%) -- 52% chance to 2HKO after Leftovers recovery
252+ SpA Life Orb Sigilyph Energy Ball vs. 240 HP / 252 SpD Solid Rock Rhyperior: 406-480 (94.1 - 111.3%) -- 62.5% chance to OHKO after Leftovers recovery
252+ SpA Life Orb Sigilyph Psychic vs. 252 HP / 4 SpD Sylveon: 142-169 (36 - 42.8%) -- 96.4% chance to 3HKO after Leftovers recovery
252 SpA Life Orb Sigilyph Energy Ball vs. 252 HP / 252+ SpD Gigalith in Sand: 122-146 (32.6 - 39%) -- 5.2% chance to 3HKO after Leftovers recovery
252 SpA Life Orb Sigilyph Heat Wave vs. 252 HP / 252+ SpD Bronzong: 148-177 (43.7 - 52.3%) -- guaranteed 3HKO after Leftovers recovery
252 SpA Life Orb Sigilyph Energy Ball vs. 240 HP / 252 SpD Solid Rock Rhyperior: 370-437 (85.8 - 101.3%) -- 6.3% chance to OHKO after Leftovers recovery
252 SpA Life Orb Sigilyph Psychic vs. 252 HP / 4 SpD Sylveon: 130-153 (32.9 - 38.8%) -- 8% chance to 3HKO after Leftovers recovery
Modest Sigilyph
252+ SpA Life Orb Sigilyph Energy Ball vs. 252 HP / 252+ SpD Gigalith in Sand: 133-159 (35.5 - 42.5%) -- 89.2% chance to 3HKO after Leftovers recovery
252+ SpA Life Orb Sigilyph Heat Wave vs. 252 HP / 252+ SpD Bronzong: 164-195 (48.5 - 57.6%) -- 52% chance to 2HKO after Leftovers recovery
252+ SpA Life Orb Sigilyph Energy Ball vs. 240 HP / 252 SpD Solid Rock Rhyperior: 406-480 (94.1 - 111.3%) -- 62.5% chance to OHKO after Leftovers recovery
252+ SpA Life Orb Sigilyph Psychic vs. 252 HP / 4 SpD Sylveon: 142-169 (36 - 42.8%) -- 96.4% chance to 3HKO after Leftovers recovery
The second set was more meme, however it was useful, Sigilyph invites Incineroar, water and rock types to come, so trick them an Sticky Barb helps to annoy, Incineroar will lose some health any time it comes, and get ride of HDB make it even more weak to chip damage, bulky waters hates dont have Leftovers, and Sigilyph can abuse them by setting up Calm Mind and ignores Toxic thanks to Magic Guard, this also works on some mons that are not as common as they used to be, but can check Sigilyph, like Umbreon.
Teams that I used: https://pokepast.es/2a74b29bcfeae1b3
On LO Sigilyph team, I decided to build a Kind of Para Spam, using Stun Spore Roserade, because Sigilyph really needs that Speed Control to outspeed stuffs like Noivern and Cobalion, and still dealing a decent damage with Modest Nature.
To conclude, I would suggest don´t use Passimian without Choice Scarf, as it needs a lot of support to use more offensive sets.
Sigilyph is an interesting pick, however it does little damage and need some hazard support to become a treat, and that is difficult considering that UU is a metagame where HDB is a common item, also Sigilyph is outclased by other Psychic types, examples are Gardevoir that hits harder with Specs and has a second good Stab on Fairy type. Reuniclus has a even higther SpAtk, and also can run Recovery + 3 Attacks with LO, both of them have basically the same checks as Sigilyph, but those checks have a difficult time trying to switch in on Gardevoir and Reuniclus than Sigilyph.