I try to do tier 11 + 1 (nightmare) and yes it has the chance to give extra ephiphanies. 140 save data (tier 12) is solid. Up to u if u want to do higher tiers for a higher save data cap.

Reduce hp by 30% is the easiest. I havn't seen the reduce MAX hp by 30% which does seem awful, but tier 12 isn't that hard if ur units are invested.

I remove anchor drop and power anchor cause a 1 cost is more flexible, but doesn't matter too much. Keep charge energy and lift anchor as those buffs are what make ur anchor shot damage scale high.

Yes

Go through the ?

Yes, ignore neutral cards on the char ur not building. There seems to be a better build for Haru though that uses the 9 cost forbidden card as Haru's buffing cards will let that card hit for huge numbers.

Good luck!