Can I play Diablo 3 online on a PS4 with my brother on the same console?

I play Diablo 3 with my brother on Xbox360, the same console, in offline mode but we would like to play online on PS4. Can we play online on the same console? I mean my brother and I as a group, like the Xbox360 offline mode: My brother and I (on same console) + other player(s) joining a party.

Is it possible? And will we need 2x PlayStation Plus for that?

Solution 1:

You can certainly play locally with your brother on the same console, of course. If you want to go online and be joined by 1 or 2 other players, I think only one of you will need a PS+ subscription but the console you are using will have to be set as her/his "Primary".

Also, I believe there is no crossplatform: only PS4 players can join PS4 players.