I thought I did clarify that- X-plan is a little below invoice (50 to 100 bucks, depending). FTE is $200 below that. A/D/Z plans are employee/retiree plans only- can't slide in through the backdoor on those things. You either qualify or you don't.
Ford has become a little more liberal with A and Z plan over the years though. Back when I bought my 99 Mustang GT, only my parents were eligible for Z plan because it would only cover an employee's children (my mother) and their spouse. A couple of years later Ford expanded it to include a broader range of family members, undoubtedly just so they could sell more vehicles. When my brother bought his 2002 Ranger he was able to qualify for the Z plan then.
Depending on the invoice price of the vehicle, I've seen A/Z plan deals be as low as a couple of thousand dollars under the invoice price. In the case of the Mustang I purchased, it would have been about $750-1500 (its been a while!) under the invoice price of the car if I'm not mistaken.