Lets just break a few things out.
Brassbank (Land owner) is owned by TTA
OEC is owned independently by TTA
OAFC is owned independently by TTA
I might be wrong but im sure only the Club Company (OAFC 2004) revenue accounts for Financial Fair Play, you cant throw in every private business you own in to the mix. Otherwise Man City would throw in Etihad Airways, Their Oil business, hotels etc and never get find.
OAFC 2004 Has no share options in any of TTA other companies therefore they will not be able to call upon this money to increase FFP.
The new stand is the end game for TTA, there way to get their money back before walking away.