I am going to just go down the list with my thoughts on each Mon.
I understand landot has very tough competition with other mons as far as being a ground type, but its role compression is pretty unique still. It's typing plus intimidate and having a powerful eq with minimal investment (if any at all) still allow it to generate a notable amount of threat on the board. I don't think Landot should be moved in the VR like at it's worst its at the bottom of A-, of the ground types it's most often compared to it's already ranked behind them (which is justified I think).
Slowbro I think is fine where he's at in A-, big dog is a bulky water with regenerator. Those two things alone help Slowbro out a lot. I think he's pretty splashable too assuming you are not running another psychic type already. It's got access to whatever status you desire, and those future sight sets that have been popping up can be very nasty for teams if they are in a negative momentum position. Bro is a bulky water done well and is a productive member of society.
Cress is weird for me. Like Ruffles stated I think it's falling out of favor, I think as a psychic type Slowbro can do most of what cress provides and better aside from the obvious lunar dance. That being said just the way that lunar dance (and hwish) operate on offensive structures alone makes it an option for teams that want it. As far as lunar dance/hwish slot on a physdef pivot I think Cress is still the best one. Could it maybe be B+, probably, but there is probably a meta cycle somewhere that it'll come back with some revenge.
Cofag I think is fine where he's at. I think it's hard to justify bringing him unless you want a spin blocker due to the number of dark types running around. Mummy as an ability I think is super slept on. It allows you to 1v1 lop assuming you don't have too much chip against you already. Cofag in my experience is super hit or miss. Like the number of games I bring him and it just sits in the back all game waiting for it's window is kind of sad. Toxic spikes in this tier aren't super noteworthy in my opinion. Either the teams are super resilient vs them with steels, flyers, levitators, or the rare poison type, and nearly every Mon that haz clears is immune to them or has nat cure, or the team just plans on winning before they can be a factor. Often times I think a t spike weakness is either a result of a bad build or someone claiming an acceptable loss condition b/c they are not particularly common in use. Maybe I misuse this spooky coffin, I want to be wrong about him, but I think he could sit in B tier and still be pretty appropriately rated.
Hippo is honestly menacing. I think the only thing stopping hippo from being used more is that Ttar is better on offensive structures. I think hippo's usage would be through the roof if ttar didn't exist. This boy is fat, he checks a lot of common threats, even special threats like volc and ZAM, he sets up sand and rocks really freeing up excadrill to be free to do whatever he wants to do freely. A- for hippo is maybe a bit too nice especially given ground type competition. I think hippo is great it just has too much competition and people frequently overlook it because ttar and other grounds get more spotlight.
Mew is the jack of all trades master of none. When building I feel like I can find something that does what a mew could do but with more refinement is most cases. What mew offers I think over other mons is role compression. Mew can do like what two mons do with a little less refinement. It learns just about every move you could possibly think of in a competitive atmosphere bar like spin/spikes and can fit in some cool spots. My issue is that it's a psychic type and stacking weaknesses to dark feels like a death sentence sometimes. I don't have much else to say, I think mew could stay the same placement though.
Seismitoad being B- is wild. Get this man B rank, at least within the top 50. Physical pivot that due to it's typing also can do well into zap and rotom. Two very common pivots. And when I say do well into them. it's not fair. Yes it does possess an Achilles heal and dilly for recovery, but I think he's underused. Depending on how you wanna invest you can be a little shiesty with this big froggo
Reun? idk what this Mon is or does. I have seen it in less than 2 games in my entire time playing oras since I restarted back in December. I would guess it's usage speaks for it's ability to do work. This is absolutely a naive based bias, but does it really fit in B-?
I love wish fish. I can see why people don't like wish fish. Bulky water with Regen. As previously stated with Slowbro these are good things to have. Regenerator and Rocky helmet are two peas and a pod for sure. Unfortunately wish fish kind of is a momentum sucker and doesn't exert a ton of offensive pressure and is horribly frail specially. like all of it's ability to tank special hits is from it's HP, it's spdef is garbage. You know it's bad when keldeo is beating you down with resisted scalds. Ultimately I think its fine where it stands.
why is tang so low still. I know he got moved higher last time he was discussed. He's a dog. Unless ground types packing toxic or fire blast he will eventually kill them all. As I previously mentioned, regenerator with rocky helm is really good. Exca doesn't like spinning into tang 800 times and crying in a green grave because he failed at his job that he generally does better than other mons with the move rapid spin. like this thing takes a beating and follows up by giving a beating back. I will go hunt down a pile of calcs if I need to.
Jellicent is cool. I like the jellyfish. It sadly has issues. can you over come those issues; yes, do you get to play into the true strength of the Mon; not really. you have to spend every possible resource available to you to perform its role. It's funny that it 100% walls keldeo and is a spinblocker, but to fully act as a spinblocker you have to run balloon or else drill just beats you anyways. Its got a bunch of really unique things going on about it, and it offers some neat roll compression, but it's hard to just drop it in on any team. IDK c or C+ seems good
I was super tired when I finished writing this. I can add more posts later if y'all got questions about specific points, if the grammar is absolutely irrefutably terrible. Please tell me or give a poopoo face react.