I can't narrow down who exactly I want on grace's team down to 6, and I think she wouldn't gain 6 pokemon until she has some sort of major life event. Think what happens in Abby camp or DDMD. The average person isn't a trainer who'd have a full team of 6. Most people would only have one to three partner pokemon.
I also don't think Grace would be particularly motivated to evolve her pokemon. Not just because she likes cute things, but it's also representative of how she's emotionally stunted/suppressed. A really good character parallel would be her giving her pokemon everstones so they never evolve.
For this reason all of her pokemon evolving requires a narrative justification/should hold weight outside of just the standard experience of pokemon evolving as they grow.
also I'm going to name more than 6 pokemon so not all of these are necessarily on her team, they could just be family pokemon. I couldn't decide who deserved to get cut from her team, oops!
Eevee -> Sylveon
I think her eevee was the first pokemon she caught herself, and thus they have a special relationship. It was also less of a catching thing, and more that they just bonded. Maybe it was the runt of it's litter, and Grace felt the need to stick up for the little one and thus chose it.
Her eevee is spunky and energetic, much like her. They're like mirrors of each other, and they do almost everything together.
Initially, she wouldn't want her eevee to evolve. It becoming a sylveon was completely by accident. She thought she could avoid it evolving because most eeveelutions require special environmental conditions/stones. Preventing it from evolving into an umbreon just meant she needed a strict bedtime schedule, and she had that anyways, but she didn't think too much about it becoming an espeon or a sylveon, thus how she accidentally bonded with her eevee too much and it happened to know a fairy type move.
This causes a rift in their relationship, as suddenly Sylveon is being neglected when it used to be her best friend. Eventually they repair their relationship as a parallel arc to Grace accepting herself and her adulthood/autonomy.
Wooloo -> Dubwool
While her eevee was the first pokemon she caught, wooloo was her first, and a gift from her mother on her birthday.
The meta reason I chose wooloo is because of sheeps significance in christianity (the whole leave the 99 story but also the dychotomy of the lion and the lamb) If you've heard me talk about Grace and the Lion and Lamb plushies I gave her, that applies. The lamb represents Grace's supposed childhood innocence, but also her own perfectionism.
To parallel this, her wooloo would be shy and timid, not very out going. I do think once you got to know it, it would actually be incredibly snooty. This wooloo is judging you despite it's adorable little eyes. It represents Grace's perfectionism, and she projects that onto everyone else too.
It's white coat is meant to represent purity, so her mother gives it an everstone so it doesn't evolve into a dubwool with it's spotted coat. (Mayhaps Grace gets a purity ring at the same time...)
Once Grace comes to terms with her Sylveon evolving, she wants to give her wooloo the choice to evolve and sees if it doesn't want the everstone.
I think in timelines where shit doesn't hit the fan, it likes staying a wooloo, but I can see in a very anime esque moment where Grace needs protecting it shakes off it's everstone and evolves to protect her. I just love the dramatic evolutions that the pokemon anime has what can I say?
Litleo -> Pyroar (male)
Wooloo was a gift from her mother, and Litleo was a gift from her father. Litleo is meant to represent her righteous anger, flipping tables, the fires of hell. It's fiery and short tempered, often getting into fights with other pokemon. Litleo doesn't get along with Grace's rockruff especially, and if she gets her impidimp from the lords, they fight constantly. (Grimsnarl and Pyroar will fight over who has the better mane/hair)
Wooloo judges you silently, but litleo judges you openly and might also light your pants on fire. Grace usually stops it from hurting people, but Max has scorch marks on his letterman because Grace didn't want to stop it once.
Rockruff -> midnight form lycanroc
Grace also just has loooooooots of wolf symbolism to me okay??? I know I've given like, three different characters Lycanrocs, but Emma has a Midday form so I'm allowing it.
Grace is VERY wolf in sheeps clothing to me, or sheep in wolfs clothing depending on how you think about it, so I had to give her one.
Rockruff was less her own pokemon and more of a family pet/a gaurd dog, but as Grace gains more pokemon she takes them all out with her to go on walks and such. This is where litleo and rockruff tustle a lot.
At some point the Chasity's have a burglar or wild pokemon banging on their door at night, and rockruff deals with the threat and evolves into a midnight form lycanroc.
The Chasitys have *heavy* stigma against Dark and Ghost types (the one exception being the Holy Spirit lol), so they kick lycanroc out despite it defending them. It becomes bitter and resentful of humans.
Depending on where she is character development wise, Grace may take care of Lycanroc in secret or shun it as well. (Eevee becoming Sylveon is sort of the catalyst of her reevaluating her beliefs)
Impidimp -> morgrem -> Grimsnarl
A gift from the lords. I just like the idea of her having a completley out of pocket FREAK of a mon. It sort of parallels her dynamic with the Axe Man. There is a hidden brutality and violence in Grace that contradicts the ways she feels she can present herself in other contexts. This isn't the controlled anger of the lion. She isn't flipping tables in the temple. She's tearing down everything.
Also grimsnarl's demon motif parallels her turning her back on God so she can align herself with the lords. Also something something Grace-Lucifer parallels.
I just like the irony of her having a grimsnarl and you can't tell me she wouldn't look badass with her cute little fluffy team and a god damn grimsnarl in the back.
Also it feeds on negative emotions so it's perfect for Grace when she goes on her corruption arcs, and you can't tell me she doesn't embody the dark fairy dual type. (Grace is very Normal, Dark and Fairy coded to me okay).
Maushold
Another family pokemon, quite literally. They have a family of three maushold because the chasitys are a family of three. They're probably of the opinion that christians should be having large families and lots of kids, so "population bomb" is a very fitting move (I do have headcanons on *why* they only had Grace but that's a separate post).
Maushold is just a cutie little goober that always sticks together. Each of the members of Maushold have slightly different personalities that mimic each member of the house.
Maushold also likes to burrow in Grace's backpack at school or cuddle up in wooloo/dubwools wool, and Pyroar's mane.
Butterfree
I literally just think she should have a butterfly pokemon because Grace is butterfly coded to me, and the butterfree line especially puts an emphasis on the whole evolution/metamorphosis aspect of pokemon. Also hannah probably gets a beedrill and I'm always on my Holywebs AU bullshit
Not many deep thoughts here, but I do think her butterfree could be pink as an homage to the anime
uhhhhhhhhhhhhhhh but yeah! those are my thoughts on grace's pokemon team. The evoution them is a little repetitive but also very relevant to grace imo.