We still don't really know what Lin's deal is, though judging by the Laura Tanzan Depths path in one timeline/alternate universe/whatever we know that Lin is simply a horrible person, through and through. Whether that's Sigmund's fault or not, I guess we'll have to see still, but I don't really think given what we know/have seen that she can be redeemed.
Sirius? Yeah fuck you Sirius. He seems to enjoy his contract -- he says Fiore Mansion would be the second house he's had to burn down like it was some kind of twisted joke. I don't see redemption for him either.
Sigmund? Not exactly Meteor, but worth talking about. It seems like he says some twisted sense of righteousness coupled with the death of his... sister? that might almost make us think his heart is in the right place in spite of what he did so wrong to the orphans. IIRC he has ship points unlike the above two aswell so maybe things might be redeemable for Sigmund.
Solaris? Sure. I think he's probably the most gray area of them all, being manipulated or worse by Lin, but it seems like he's really just doing what his family has had to for generations without really questioning it too much. I suspect there'll be some kind of Solaris-tries-to-stop-Lin-but-its-too-late-and-he-dies moment but who knows.
Taka? I'm on the Zekrom path and heard about the other path, so I can't really comment on that one for apparent reasons. What I do think, and thought by choosing to battle him in WTC, is that he can operate as either the conscientious objector or the saboteur within Meteor, whichever doesn't get him nixed in this path. Obviously everything between the Titania-Taka-Us triangle already asked the question regarding him, but he's certainly redeemable nonetheless.
ZEL? Well, it seems like Zero is a savage and agrees wholly with Meteor, so I guess we'll have to see with him. Lumi is calculating but probably in a similar boat to Flobot morality wise, and Eve is clearly supposed to be good. Are they even still alive? I know we saw Zero come out of "devon" but not those two.
Elias? As you may or may not know, I kinda despise religious fanatics that would use that as their justification for their actions, especially those taking away civil rights, and it seems like Elias is just that at times. Yet, it seems like all he's PERSONALLY done is wanted his daughter back and tried to get his apprentice an elite four position (though likely unethically), so idk. He might have a perfectly sound redemption arc or be controlled by the powers he seeks to possess. Then again he tried to... sacrifice...? Luna, so maybe not. He seems like he is grateful to the lord for his sight and so perhaps obligation drives him, which I could see turning against him and making him see reason again.
As for the grunts, again, I don't know. Some probably drank Solaris' Kool-Aid and some seek power Lin can bring to the table, others simply want a place in the new world. I don't think the grunts for the most part are evil on their own.