There should be less buffering if you get the Stream tier.
Kinda - assuming you buy a two device package when you log in with the laptop you might bump your wife or your phone. To avoid that, go to log off.com on the phone before logging into the laptop.
I think the discussion was about the base fare, not the overall cost. It is very rare for a TA to openly advertise/book the base fare as anything other than the fare shown on the RCI web site (unless the RCI web site has some pricing glitch).
Not sure where you are reading that but you generally don't need any of that - at most the immigration officer at your first point of entry may ask why you are visiting.
On the app, you have fewer steps to be able to choose a check in time (and do the rest later) have the ability to scan your passport and take a selfie - otherwise, they are the same.
You didn’t win - there would be a charge on your credit card and a new cabin assignment (and likely an email). Bids sometimes get stuck like that - you may need to call to unlock/cancel it.