Dinosaurs never left

Simple answer. No. It's impossible to bring back actual copies of Non-avian dinosaurs. Even if we manage to reverse-engineer some birds it's not gonna be an actual non-avian dinosaur. Just some artificially-engineered bird.

No

Maybe

They did find t rex DNA but it was not very well preserves but it took destroying a rex leg bone to get though

No

There are so many movies saying that its a bad idea.