Well, the rules don't say you -can't- use nonrare creatures, only that you must use all the nonrare creatures in the duo, so it looks to me like squid/pharaoh/nymphs would be legal, just not required. It also sounds like spells would fall into the same optional category. From my interpretation (which is by no means official) I'd say that the dimshield deck is illegal (dims are banned permanents; I think the silences are fine) and the fire/water deck is illegal (not 50/50), but I think the light/earth deck and the death/time deck would both be legal, assuming you didn't miss any of the nonrare creatures; I didn't bother to check that.
Quantum pillars would be legal, but I think just to simplify the rules that they should be banned. The rest of the 'other' cards are already banned due to being permanents, and quantum pillars would probably just cause unnecessary confusion with the 50/50 rule.