I'm in four FFPC superflex leagues, but last year was my first year doing that format in FFPC. I took over two orphans and did two startups. In one orphan, I had Russell Wilson and Winston, who was still a Buc when I took over the team, so I was kinda pissed when he got cut. To your point: In the rookie/vet draft, I was on the clock at the 2.02 and Jared Stidham was there. I know it seems dumb now that the Pats would have gone into the season with Stidham as starter, but at the time, it seemed about a 50/50 chance. So I took him. It hurts to see all the rookies I passed on, but I chalk it up to being somewhat new to the format. (A few weeks later, I took a shot and traded Winston for Cam straight up, which worked out for about the first month of the season.)
Mariota isn't available in any of my SF leagues, but I don't think I'd take him at the 1.02 when literally any other rookie at that spot will have much more trade value and for much longer. Mariota will likely be considered a stop-gap QB anywhere he ends up, unless he pulls a Tannehill, but, even then, I don't see anyone trading the 1.02 for Tanny. Using Stidham as an example, he was taken as early as the 1.10 in FFPC rookie drafts last May, and his ADP was 3.01 in the 31 leagues where he was drafted. I think a good Mariota comp is Bridgewater, who was the unquestioned starter for Carolina and was available in only three SF rookie drafts, where he was taken at the 2.01, 2.09 and 3.04.