A T-tail does not cause deep stall, although it may well aggravate it when it happens.
The deep stall is caused by tip stall on a swept wing, which causes the lift centre to move inboard and forward.
Absolutely correct. B2N2, I don't find the definition above incomplete.
I agree that that FAA figures give a different perspective, but in my opinion they are depicting a slight different scenario, where the wing is NOT actually stalled even if close to. By design, in the real stall (with weight and balance within certified limits of course) the nose should drop forward so giving better authority to the elevators while in the real deep stall that doesn't happen, because the CG keeps moving forward to a point that the recovery is virtually impossible. Anyway, imho, i think that the same term "deep stall" is used to define 2 different situations.
FB