Agreed, other than Cathy and Arieth (who is hilarious as ever), Swyper just feels like busy work. Nicole is good sexting if you want it, and we at least see her in the real world so it might become relevant some day. But for the most part I'm happy to skip Swyper, whatever Derek says.
In theory she could be talking to Chad on a pinktooth headset, but it would be a real stretch. Who has phone sex when they're jogging on a treadmill? Wrong type of heavy breathing! I'd certainly call foul if that turns out to be the reveal.
Absolutely, the gate for the Episode 5 lewd scene really should have been making a move on Bella in Episode 4. I suspect that wasn't done so people who stayed with Sage could still have a shot at it, but as you say it completely alters the context of the way the MC keeps hitting on her feels without her silent assent in the pool.