Yea, a really good buddy of mine had two small Puffers (maybe Figure 8's) in his 72 bowfront, with Malawi haps and frontosa, and they were so aggressive towards the other fish he ended up having to rehome them (they had a really nasty method of biting out chunks from the fish).
Don't know if it's the same for all pufferfish though, so definitely do your research. Oh and as far as the salinity goes, you should probably do as recommended and make your tank slightly brackish, but if it's any consolation, that friend of mine has had them for 2 years in freshwater (pH 8.2, hard), and they're still fat and healthy.
120G FW--All Male African Haps and Peacocks
75G SW--Eventual Reef Build (work in progress)