What to keep/switch in my party

Pajay Lvl. 47 (Not leaving party)
Eletux Lvl. 51 (Not leaving party)
S51-A Lvl. 42 (Currently training) (Not leaving party)
Evee Lvl. 48 (Haven't decided on which evelution I want to do yet, but I've counted out Jolteon, Vaporeon, and Nucleon)
Baaschaaf Lvl 38 (Just got, currently training)
My last slot is empty, so obviously I need to put something there, not sure what type I should prioritize for the party though.

I'm training around route 16 right now (Snowy as anywhere but hell mountain) so I can get my S51-A leveled up to 55 at the very least since it has very good moves against ice type along with Pajay.

Mostly I just need to know what Eeveelution I should choose and if I really should exchange one of my party pokemon out. I also need a sixth pokemon.

Nucleon is a very good option, seeing as it gets Nuclear Hyper Voice thanks to its ability. (Although, you might want to try to teach it Shadow Ball before evolving it, and HP Fire if it has such.)

As for the sixth slot...maybe the Rock/Ice fossil or the Ice/Dragon type you can catch in the snow route between Silverport and Snowbank.

Just so you know, the 7th gym leader's ace is a lv 62 mega pokemon, so you may want to train accordingly.

Farfurr would actually be a good choice here it gives you another good physical attacker, and it's a bulky ice/dragon type thanks to the fur coat ability it can have.

Seeing as the last gym uses a few dragons it may be worth getting some fairy coverage, winotinger could replace baaschaff, Alpico would give fairy ice coverage against the bosses fafurr, sylveon is cute af.

If you have 4 hours to waste on voltorb flip then a Tracton is great for the last gym, survive one turn to use shift gear and proceed to one hit everything using either steel head or dragon claw, you always get first turn thanks to speed boost

Sounds neat, gonna head back and grab the pretty ribbon and eevee house I missed and also get a winotiger.

Venisi gives you one in what I call the eevee house, and I think you can buy 1 in the dept Mart on the 5th floor.

INeverSavedMyGame, your profile picture gets me everytime!

Hah, glad you like it

It's from a funny animation made on YT, I think you'll find part one if you look up leviosaaa