Yeah, I really think it depends on many factors with each puffer. Mainly their personality and size.
I have had a couple of porcupine puffers that did fine in my reef tank, didn't touch anything. Left the cleaner & pep shrimps alone, even the crabs were safe. I find they are all fine until the puffer gets bigger, then he changes. I tried a dogface puffer in a reef once...
ya he took a sample of everything he could before I got him out.
With adding two puffers together.. its another stab and miss. Each fish I find is different. My porcupine HATES my star & stripe puffer.. but maybe its just cause my porkie is bigger then him. So ya never know till you try it. As long as you have the room to seperate if you need be, your good to go.
Best of luck. The Mappa may be a teenie aggressive but what a beautiful fish it is.
Lee