I can't see any way that West Ham's skill [fortune] at securing an inexpensive rented stadium would contravene FFP regulations. All it does is to reduce their running costs, which makes them more viable by FFP standards, not less.
The downside for them is that they have no asset. They don't own anything that is worth money. Tottenham has a huge pile of borrowing to pay off, but once we've done that, assisted by the receipts from the residential development, one hopes, we'll have a property worth millions, along with many other property assets in the neighbourhood that are worth further millions. West Ham just have an ever-depreciating lease.
It's a contrast between short-term money-saving and long-term investment.
Club infrastructure is not included in FFP.