From what little I’ve seen — what little’s available — I don’t see much reason to expect it to be. Spike is wingless, Sugarcube Corner is the center of operations, and the Corner also seems to have a stash of mysterious magic potions — none of these things jibe with G4.
Most of FIM’s writers stopped being consistent after like Season 4, and both Keating Rogers, and M.A. Larson (two of the more notable writers for FIM) quit after Season 5, with excerpts of a script from Larson being used in Season 7.
It could go for a while, but it’d be just like FIM where writers stopped being consistent after a while.
I doubt we’ll be seeing most characters post Season 2 except Starlight Glimmer and Cozy Glow, maybe some other villains too. I could also see maybe Flurry Heart. Spur has a 1 in Graham’s Number chance of being a background cameo, and she’s probably the most likely Season 9 character after Grogar and Luster Dawn; and forget about unnamed background ponies (and I’m pretty sure Hasbro technically doesn’t even own Spur anyway)