-- Tentacruel
I like what you're trying to do with Tentacruel, but he could use a couple of tweaks. Firstly, an EV spread of 252 HP/ 120 Def/ 64 SAtk/ 72 SDef with a Calm nature gives you identical HP, SAtk and SDef, but a whopping 13 more points of defense effectively for free. (When EVing Poikemon, it is always superior to boost the highest stat with the nature unless you need it to hit some sort of benchmark. This is because the nature is a flat 10% increase, so you will get more points out of a higher stat.)
Acid Spray is a cool move, but I feel the slot could be better served. You currently have a HUGE weakness to DDnite, as it is able to come in on every Pokemon except Latios, DD up with Multiscale to protect it then sweep. After a single Dragon Dance, it will outrun every Pokemon you have and your only hope of beating it is baiting Outrage and going to Ferrothorn, which can be beaten with good prediction. Giving Tentacruel Ice Beam decreases the number of Pokemon Dragonite can setup on. I'll cover more measures against it on other team members.
-- Latios
I don't have too much to criticise with this set, actually. My preference is for Expert Belt over Life Orb to bluff a Choice item, but either can work. A Timid nature is also absolutely imperative, because without it Latios' glorious 110 base speed is wasted - a Modest Latios can't even outrun base 100s. The moveset should also be tweaked - Surf and Draco Meteor provide excellent coverage, while the remaining two slots are up for grabs. Psyshock cannot 2HKO 252/252+ve Blissey without Choice Specs, so I feel it is wasted here. In its place, I suggest Thunderbolt and either HP Fire or Dragon Pulse. HP Fire hits Ferrothorn hard, who does a good job of walling this team overall, especially in rain. However, it necessitates an imperfect speed IV, which prevents you from tying with other base 110s like Gengar and opposing Latios in a pinch. Dragon Pulse is a solid, reliable cleaning option that is very useful lategamne to avoid the spatk drops from Draco Meteor.
-- Gengar
I know you like Hex/Venoshock, but I have to agree that Sub/Disable is really better than every other Gengar set by a long way. Shadow Ball and Focus Blast provide flawless coverage anyway, and free Substitutes are extremely easy to procure. Once behind a sub, only prediction can save the opponent from heavy damage. Use the standard Sub/Disable set from the analysis. Gengar also give you a solid CM Reuniclus check, as disabling the right move will cripple it.
-- Landorus
As others have said, even with Sheer Force, physical Landorus is better than special. A Scarf set with EarthQuake/Stone Edge/U-turn/Hidden Power [Ice] can now revenge +1 Dragonite and act as a general check to various sweepers. You can afford to run a Jolly Nature, as HP Ice will still smash Gliscor to pieces - the only reason for using it. Landorus can also revenge +1 Salamence, another big threat. The loss os Extrasensory is fine, because Gengar will beat most fighting types anyway.
-- Ferrothorn
I'm not sure what exactly Ferrothorn does for the team. Sure, he provides Spikes, but he also kills you offensive momentum whenever he switches in. I second the suggestion of a Scizor instead. CB Scizor can break frail threats like Alakazam, act as a back-up check in situations where Landorus is dead (though Bullet Punch will usually require decent preliminary damage to finish things off). It also somewhat alleviates your CB Terrakion weakness, though is it still a very large threat.
-- Infernape
Finally, I feel Infernape isn't actually achieving a whole lot. Sure he's fast and he hits fairly well, but an Offensive DDnite would be a much more potent replacement, while also checking sun better. (Another threat) Adamant Max Attack/Speed with DD/Outrage/Extremespeed/Fire Punch and a Lum Berry can set up on almost anything if SR is off the field and sweep weakened teams without breaking a sweat.
Anyway GL, i like the team's Tspikes "theme" but some sets are not optimal.
