I own the BB LHS cordovan loafers, and I can tell you that they fit exactly like Alden's Van last (ie the non-BB version). Further, I have the BB tassel loafers, which fit exactly like Alden's Aberdeen last. Based off these two data points, I am going to say that they BB Aldens fit exactly like their Alden counterparts. The LHS are the exact same shoe, while the loafers have stitching by the heel.
As this was my follow-up question regarding the LHS, the Van last sizes very closely to the Barrie.
Lastly, yes, as far as I know, the BB 30% off is the most dependable way to get a significant discount on Alden cordovan.
The Alden for BB medallion cap toe blucher, tassels, full strap, and LHS are all built on the same lasts as the stock Alden models. Such is not the case with the Alden for BB PTB, Wingtip bal, perf cap toe bal, and straight tip bal.
[Edit: Sorry for the redundancy; I didn't read ahead before posting.]