I mean , guys , does the staff's attack affect the healing / support power from skills like Healing / First Aid / Ougi Rapid Storm / .....

Cuz im a spear class , but i kinda mixed it with staffs so .. you know , just wondering if i need to find a strong staff too , or something like Oak staff with high skill level is ok
-thanks

Staff attack affects everything except rapid storm, itaden's grace and god speed (from the skills that are available atm). So.. basically anything without a fixed value.

Oak staff wouldn't be able to heal much at high levels. I guess it'd only be ok if you just use it for movement speed and maybe invig, although invig would be better with higher attack, too.