But u don't have passive 2 max though, therefore it won't make much different.

As for mystery, I'd choose +2 for more damage.

ofc it's much different, I'm scaling nin also, and the amount of times they hit me adds up

I say focus on getting your scaling done first, then worry about her self heal, then for the final bit, work on mystery.

Hey, from my personnal experience, mystery Y+1 is way better, especially when come 1v1. (we got kushina skill trial since 3 weeks in fr servers)
Also, chase is a must have, since it reduce your own cd. If you land mystery + double chase, you only need to be hit 1 time to reset for next round

If i was you, i would go for chase, then scaling, then self healing and then auto