I would guess for the anime/cartoon, they'd look 2D, but you can go around them and you can see the rest of their animated bodies.

It's possible, you just gotta improve the vividness/clarity of the dream.

I don't know why they satisfy you, but try expecting an epic fight when you punch a DC.

Keep Dreaming and your time spans might increase, but IDK really. I don't know about 30 min. of real time, but I know a few hours of dreaming in a 10 min. nap or REM sleep.