Quote Originally Posted by Unregistered View Post
do multiple copies of the phantom weapons stack?
Theoretically, they do, and (especially with SSR Diabolos in a future update) could potentially enable for a mixed element team. The issue is getting more than 4 copies of the phantom weapon you're aiming for (assuming you're MLB'ing and leveling them before adding them to your grid), since they don't drop often from Ragnarok raids, and you have no control over which one you get when they do drop.

However, assuming multiples of the same phantom weapon count towards the 6-of-a-kind requirement, only the second skill stacks. The first skill's increase to base stats is applied once, and having multiple of the same phantom weapon will not improve base stats further.