It takes two on the same ps4?

Can you play it takes two with someone on the SAME ps4? I know it can be done both online and locally, but I wonder if you need two separate devices or not.

Does it support split screen?

Yes you can.

The whole game is split screen, even if you play online you can see what the other is doing

I don't know do not know. But if you do play it yourself, you must have noticed the 2 player function in the menu.