Need advice on my next rank up...

ManfréaBolgen

I'm a bit short on resources so I can only do one of these. I currently have 3 r5 5* (CapIW, Sparky, Domino) and a r2 6* (havok)... everyone but doom is awakened... I still haven't explored act 5, haven't even attempted act 6 past the first chapter... did one run through variants 2, 3 and 4... ideally I'd want to work on story quests next and then move on to variants, then lol (hopefully)... any suggestions? also, side note, I have a generic ag, should I use it on doom?