Full support is not my thing but here is some stuff I learned.
Blessing and Sacrament are probably the best priest buffs.
I heard Monstrance scaling is not that good.
This build will be a total pain to play if you don’t have anyone to kill stuff for you.
This is not ragnarok i believe everyone should deal some damage.
You will need int to get better heals
Resurection doesn’t need more than 1 level
Imho you should get Krivis as second class and get zaibas so you will be able to carry your own weight at least at the start.