1) Preferred trial may only be used once every other year, and if you don't earn the required miles (flying US Airways operated flights only, no credit card miles, etc.), you lose status. This has been going on in this form for some time now, so not likely to be changed in my opinion.

2) Only flight miles are preferred miles, and for the purposes of the preferred trial, only miles earned on US Airways/ express operated flights count

3) Have never used this, no idea what you're referring to.

In any case, Preferred does not entitle you to free upgrades on transatlantic, only north & central america and caribbean. Tickets booked with miles are never eligible for free or mileage upgrades. For transatlantic, purchased tickets must exceed $1400 each round trip in value to be eligible to upgrade with miles.

In my opinion, if your primary goal is to fly Business Class to Europe, Preferred will not help you out at all. There is the possibility 24 hours prior to departure to purchase an upgrade over the phone for $500 per seat each way, based on availability. Call the reservations line 24 hours prior to departure to inquire if seats are available.