We already know that Doctor Octopus is the same version from Spider-Man 2 and he comes from the moment at the river where he died. Now I will try to explain my theories about where other villains come from.
I believe Max comes from that moment where he exploded after Spider-Man overcharged him and I think he is using that new suit we saw in the trailer to prevent same thing from happening.
We all know Lizard didn’t die so we have to think a bit more creative here. I guess he comes from the moment he was falling from the tower because that is the only moment that he thought he was going to die. Hearing other villains stories might make him believe that he won’t survive that fall.
We only see one shot of Norman’s suit from Spider-Man 1 and that shot doesn’t look like good CGI. I believe they tried to hide his damaged suit because he might be coming from that last fight with Tobey’s Spider-Man.
In Spider-Man 3 there was a perfect scene for them to make Flint think he is dead and that is the moment where he fought Black Suit Spider-Man in the sewers. He looked real scared when he saw what water did to him and that is the perfect moment for him to come.
We already know he is coming from the river scene in Spider-Man 2. I just wanted to say that I believe he got teleported while he was drowning because his hair looks like he just came out of water.
I hope you all liked my opinions about where these villains are coming from. I think these are the perfect moments for them to believe they’ll die. If you guys have another theories don’t forget to explain those in comments.