I agree that it seems likely that the Ford GT will be one of the sets, but for the other one, what do people think the odds are of it being an M-Sport Ford Fiesta WRC? Certainly M-Sport got the champions part down, what with taking gold, silver and bronze in the 2017 World Rally Championship.
I'm also flummoxed that Porsche is getting not one but three cars this year, since we already had a 919, they don't do any motorsport any more beyond GT racing, and--let's be honest here--all 911s look the same.
With Ford not doing Formula 1 either, I'm also super bummed that one of the two Ferrari sets will pretty much have to be another Scuderia F1 car. I'm actually betting the $100 set will be a re-release of 75913 (the truck), because this seems to be the year of re-releases. That leaves the single-car set, which will probably be a 488 GTB (hopefully they'll do the AMG-Merc thing and make it road/track convertible), which is too bad, because I would love to see a 250LM (we could re-create Le Mans '69 with the 917 and the GT40!)
Edit: if the September leak is accurate (and this new leak seems to be confirming it), then there's another option for the Ferraris that would actually be pretty cool: three historic F1 cars, maybe Ascari's 500, Lauda's 312T and Schumacher's F2001?