I don't think Toby is going to die anytime soon, at least. I think he was just deep into depression. Maybe after losing a parent or another miscarriage.
I loved seeing Randall and Kevin "normal" again and not wallowing or preoccupied or even making it all about them.
I'm assuming future Randall was talking about Deja, only because he said he's not ready yet either. To me, if it was Beth or the youngest daughter, he'd be by their side from the get go. Or wouldn't hesitate to visit a grave. But my initial thought was someone was sick, and they didn't want to see that person ill in the hospital.
Could future Kevin be adopting from Vietnam, and was just looking at the photo? This show likes its twists.