Hi Joanna,
I'm a shareholder - although haven't used the benefits as yet.
The 4 for 3 style offers cannot be discounted by the Shareholders discount as you suggest.
Using the Shareholders booking line you can book a package and obtain the necessary discounts - I believe it can be longer than two days - although you can only book 2 rooms in any one booking (used to be 3 rooms).
Having typed that I was just looking at the Shareholders page on Eurodisney.com - and it just suggest it is only 2 nights - although depends on how you read it, I could imply that the 2nights is only is you are booking room only.
2) Disney® Hotels only:
Disneyland® Hotel, Disney's Hotel New York®, Disney's Newport Bay Club®, Disney's Sequoia Lodge®, Disney's Hotel Cheyenne®, Disney's Hotel Santa Fe®, Disney's Davy Crockett Ranch®. Booking through the dedicated line only. + 33 (0) 1 60 30 60 72. Hotels packages excluding transport. For Hotel stays, on "Classic" packages or rooms only (2 consecutive nights and 2 rooms per stay). Suites, Family rooms and Castle Club excluded, maximum 2 rooms per stay, prepayment according to the general sales terms valid at the time of booking, cannot be combined with any other promotional offer.
Personally like you, we tend to go using a 3 for 2, 4 for 3 style offer, and I believe offer works out cheaper than using the discount, given that we are new at this, and still feel it necessary to stop over at a Disney hotel. Having done some pricing in teh last week or so, I think next time (after November) we will probably stay Holiday Inn or similar - and then it will be booked independantly.
As for the AP - yes, it seems that some of the shareholders on this site also hold APs. The 'only' benefits I guess are that they have 'free' entryto the park, and further discounts not offered by the shareholders club. The complete list can be seen at
http://www.dlp.info/HintsInfos/Passport/Dream.htm (based on the Dream Passport). Examples however are a one time 20% restuarant discount (per AP), one time 20% shopping discount, higher room-only discount rate, free kids stoller hire etc.
Passports is something that I'm looking at to purchase when we visit in November.