I've updated the first post with recent info you've provided.
I'm still looking to confirm Wheelspin or not for:
1964 Ford GT40 MkI
2008 Lamborghini Reventon Forza Edition
1973 Land Rover Range Rover
2004 Maserati MC12 Forza Edition
I found them in Auction House listings but don't know the original source. I haven't gotten into Ranked Adventure - has anyone noticed these or different reward cars in Autumn compared to Summer?
I think the only model that is completely unknown is the 1973 Ford Capri RS3100 Forza Edition since I haven't found it in the Auction House.
In searching the Auction House for Source > Prize Cars, these models appear to be either My Horizon Life or Forzathon Shop models:
2017 Ferrari 812 Superfast (Forzathon Shop, Summer)
1985 Ford RS200 Evolution (Dirt Racing, level #?)
2006 Hummer H1 Alpha (?)
2014 Lamborghini Huracan LP 610-4 (Road Racing, level 4)
2016 Jeep Trailcat (Cross Country, level #?)
2009 Lotus 2-Eleven (?)
1995 Nissan NISMO GT-R LM (?)
2010 Noble M600 (Speed Trap, level #?)
2015 Porsche Cayman GTS (Road Racing, level 7)
2017 Ram 2500 Power Wagon (Dirt Racing, level #?)
2016 Zenvo ST1 (World's Fastest Rentals, 30 stars)
2015 Ultima Evolution Coupe 1020 (Drag Strip, level 4)