SCVI is a SCI reboot. SCVII might focus on SCII - IV because all of those games take place in the same year. Cassie, Setsuka, Tira, Amy & Hilde(SCVI DLC) will be on the main roster because they were new characters in thier respective games.
If SC VII actually will be a sequel for SC VI yeah that's possible.
Because same thing didn't happen for SCV - SCVI.
Let's just hope characters like her and Setsuka don't turn into DLC bait this game onwards. That would be really sad
Srsly tho, she has a chance of being DLC at the very least.