FM7 and these forzathon challenges are very buggy. If you pick the right car and event you can negotiate through them. I did and got all 3 rewards. This YouTube video helped.
THIS IS MOTORSPORT 7: Didn't work the first time (with the 1970 Dodge Coronet Super Bee), so I tried a different car - still didn't work. After I completed the other two challenges I came back and the Dodge Coronet worked fine (so perhaps, do the other two first). For Track Toys I used the 1999 Lotus Elise Series 1. For the Forza Touring Cars I used one of the Honda cars (#5). For the GT Racing Reborn cars I used the 1975 #25 BMW Motorsport. Other cars may work, but these are the ones that worked for me.
GOING FOR THE DISTANCE: See that specific challenge for my comments on that one.
CLEAN SWEEP: The least buggy challenge. Follow the suggestions in the YouTube video.
NOTE: Where you do NOT have to do a specific number of laps on a given track you can use Freeplay and set up a 30 sec. Timed race with no Drivatars.