1. Agreed, could be sender
2. Take off the TB and clean it. Pull the IAC out and clean both the pintle (round nose of it) and the hole it sits in. This is the most likely cause. PS..stop bouncing the engine off the rev limiter.
3. Yes, that is your power steering pump trying to push more fluid to a fully pinned rack. Normal.
4. The vehicle was not designed and no one makes a direct kit for it. Most will only do the costly conversion if they want to do it for the performance. Most likely it's not cost effective for you to consider it.
