1. It doesn't seem like they're that interested in it and when you think about it, why would they be? They've found a niche they're highly respected in and I can't imagine they're lacking work, so making original games is a risk in comparison.
2. Sure, there's no reason why it can't. I don't think Sony had any indie games last year, probably because a decent chunk of the conference was taken up by VR, but Firewatch got a pretty nice spot during their 2015 conference. TBH I've been kinda disappointed by the lack of indie games in their conferences the last couple of years. Their indie segment in 2013 was a real highlight at the time and it's not like they've been lacking great indie games to show more recently.
Resistance 2 didn't have a co-op campaign, its campaign was single player only, co-op was limited to the team-based missions (which btw, were way ahead of their time). You might be thinking of Resistance 3.