Pardoner spell shop may only sell buffs which require items (blessing, aspersion, sacrament).
Pardoner simony => craft scrolls (daino is useful to craft, at lvl 1 simony your profit is best). You may craft cure scroll to use double cure too.
Discern evil -> extend debuffs. You do not have any useful debuff to extend in your build, but you could extend your party debuffs.
Indulgentia does not have very nice damage. It is a single hit. It is quite useful to get mob aggro though, the range is quite big. At PvP you can free players from Psychokino Raise when you use indulgentia.
Taoist & krivis is taken to amplify zaibas lightning damage. I recommend krivis3 (zaibas 15) if you want to maximize damage.
Damage : krivis3 zaibas 15 + Taoist Storm Calling
Krivis3 support: melstis for earthtower (need diev3 party member for ausrine buff).
Cler2 support: heal 10, divine might, safety zone attribute. Get Cure max if you go INT build.
Example:
Cler2 - Kriv3 - Miko - X - Taoist. Nuke oriented playstyle (zaibas storm). Party support through cler2, and krivis (daino, melstis), and taoist (invis, storm call attribute to boost melee damage too).
Example2:
Cler2 - X X X - Miko - PD2. DoT playstyle through plague doc poison and burn. Bonus party CC immunity. Duration of bloodletting is lower at PvP though.