After I install base rom with wipe Cache & Dalvik Cache, I need to do wipe before I install add-on and gapps?
C'mon man, there's a reason its called 'ADD-ON', not 'SUBTRACT & ADD ON'
Cache wipe isn't considered a ' dangerous wipe'. Its a standard protocol, to remove the unwanted temporary files by the OS or apps.
Just wipe cache (& dalvik) & flash whatever you like.