No. Among the Julio-Claudians only Augustus and Claudius were deified. Domitian was excluded also among the Flavians, and when you get to Christian emperors deification becomes a significant theological problem. I hadn't thought about it before; between Augustus and Vespasian (if my math is working; it doesn't always) there were seven emperors, of which only one was deified (I think). It's odd then that Vespasian is supposed to have joked on his deathbed that he feared he was about to become a god. I should look into that.

I'll leave comments on cult practice to the religious experts around here.

Hi, I've answered your questions in other posts a while ago. Regarding if emperors were commonly deified and How they were worshipped and understood as gods. I'll of course be happy to answer any follow-ups you might have, but these posts should answer your initial questions.

Not only not all emperors where deified after their death, some were actually so reviled that they got the opposite treatment; the Senate voted for "Damnatio memoriae", the damnation of the memory.

That meant that the record of the emperor were expunged, hist statues smashed, his name chiseled away from stone inscriptions and so one.

A famous emperor to get this treatment was Domitian after he was assassinated.