Let's take the domestic engine off the table, that's not even a question (there's no way Turkey will produce an engine in a decade, period.) As I said, if they can source an engine (the US is not the only solution), then I think the TFX is still in the game.
Yes, if ... and that if is connected to several ??? Which engine could be an option?
Off the shelf for a fighter in that class it could only be the F100 or F110 and if the US deny this, it's over from the Western side ... all European ones are smaller and less powerful, so they need either a redesign (takes times and costs money), which delays the fighter. Even more the way how Turkey or shall I say its president against several European countries like France, Germany I see no option for the EJ200 nor the M88 ... and so only a Russian or Chinese design could fit in that class but this would make the rift between NATO and Turkey even wider.
IMO there si simply NO chance for this project to succeed as long as there is not a dramatic reduction in Turkey's attitude!