Your Scavo vases have little if any connection at all. The two paler examples might be from Murano, there seems to have been a short lived fashion for similar in the 60s or 70s, not a clue about the darker square example but suspect all are relatively modern. This kind of 'aged' glass is made for museums and antiquity sites around the globe.
Back to your dish, is it formed from a single piece of glass or is the foot added? How big is it?