Yes to all of your questions.
The primary purpose of the foil is to push through the stall by braising, which means a fairly tight seal and maybe a little added liquid (or letting the meats own juices perform that magic.
Covering a pan with foil is purely convenience, and it works basically the same as above (but not quite as effectively from the braising perspective). It is a lot easier to manage a pan than meat wrapped in foil, especially if you wish to reserve the juices.
When I foil meat, if I get a good seal with one layer of foil (and it is HD foil) then I am happy with that. OTherwise you need more layers to make sure it holds together and doesn't tear or puncture as you move it to the cooker.
I get a realy long strip of foil, and place the meat centered on one half of the foil, then take the other half to fold over, bring the sheets together as cleanly as possible, then crimp up and seal tightly.
Because you are pushing through the stall, if you don't check your meat, you may find yourself overcooking it before you know it on your first few attempts.
(wait a minute....what the FARK am I doing posting over here in Q-Talk???)