Could you elaborate on the Reaper part? Isn't banish a 1 per mission thing? How would a strategy that relies on a reaper never being revealed work?

I use reapers with my SPARKs to scout ahead and remote detonate stuff, but his contribution compared to my SPARKs is minor so i wouldn't call them strongest. Most useful definitely but I won't use the word "strong" to describe them if they're not killing the majority of enemies.

I don't think I'm lucky. I kill gatekeepers and sectopods on the turn I reveal them with overdrives to spare. So my thinking is that on higher difficulties, I'll still kill the gatekeeper and sectopods on the turn i reveal them but maybe not their escorts.