I understand Vent/Plat handle priority club a bit different I've looked over the thread but I'm still a bit confused:

Does Plat status on priority club's benefit which lists "Priority check" in allow a member to go to invited guest check in?

What about Extended check out? Would I be able to get a check out time of 3 or does it just push it from 11 to 12?

A lesser concern but what about room upgrade for plat? I don't really care as I like even their base level rooms a lot but just interested.

If not how about Ambassador/RA (I mostly have my answer for last question for A/RA)?