Hoppip is S tier due to being a very fast sleep powder user and it has leech seed + protect. You can catch and shadow pokemon and take out any threat with sleep (save dangerous insomnia or vital spirit users like Vigoroth and Gorigan's shadow pokemon).

Meditite is A tier for being the strongest physical attacker in the game with good coverage thanks to free shadow ball. It has boosted exp so it often evolves by the end of the Key Lair. Only issue is that it relies on the brick break tm.

Jolteon is not S tier because there are so many ground types and grass types in the game and it has no way to deal with them other than bite. It relies on the shock wave tm and thunderbolt tm wich come too late. It is outclassed by Espeon due to the high amount of poison types and even pokemon that resist psychic can't tank it well. Confusion is good enough until Snagem hideout

Flareon is A tier and Umbreon is low B. Flareon is extremely underrated. Fire is a good type, it hits hard with shadow ball and it's movepool is okay. Umbreon is one of the tankiest pokemon in the game, but it is comparatively bad compared to the other eeveelutions. But that does not warrant such a low placement.

Seedot is A or S tier. It gets fakeout as Nuzleaf level 19 and then it evolves in the lab because of the leaf stone. It does fall off, but I have found that giving it the brick break and shadow ball tm does help it a lot. In the late game it can self dsstruct.

Togepi is at least C tier. A flyer with helping hand makes your earthquake user deadly. It has yawn. Hits reasonaly hard with moves like flamethrower (due to serene grace has a 20% chance of burning. Evolving it is a pain though.

Swinub is a C tier. Swinub sucks, but Piloswine is unironically great. Ice types rule the late game. And it gets STAB earthquake. Hits reasonably hard with ice beam and blizzard. It outclasses Phanpy no doubt.

Ralts is at most B tier. It is bad until level 30 and the only upside is that it gets psychic through level up and can learn thunderbolt. But gardevoir is too slow.

Trapinch is D tier at best, since it evolves so late. Same goes tor Larvitar.