Between the Playstation party games with phones and Matterfall I would say they are worried about Nintendo and are trying to catch some of their demographic.
I don't think so. It's clear the ps4 is the number one home console. Sony is putting its eggs in that and the VR basket, letting Nintendo claim the portable side of things, which is fine.
To be honest though, I'm pretty underwhelmed thus far with e3. Aside from the Shadow of the Colossus remake (oh look, another remake), nothing has really stood out. I hope Nintendo has a nice surprise or two.
It looks like Sony shareholders are worried about Nintendo. Excluding themselves from crossplay doesn't benefit playstation players, but if your friend owns a playstation and you want to play with them you now ha e to own a playstation. Sounds like a defensive move to me.