Ford said 6 cars would be built, 2 for the IMSA team, 2 for the WEC team and a spare chassis for each. There's a chance the WEC 66 was written off last weekend at Spa, so we may now be down to 5 cars, now. They've said they won't look into selling them to private teams while the factory program is going as supporting customer teams adds a huge, additional element to the program, but said they might consider selling them to private teams after the factory program is done. Time will tell...
As far as who actually owns the cars right now, I don't know. Often times the cars are pre-sold to collectors as a means of raising capital for the racing program, but I have no idea if that's the case here. I have to imagine one will go into the Henry Ford Museum, especially if they win Le Mans.