Unlike most lottery teams, the Ducks have a plethora of top-10 picks already as well as picks outside the top-10 that are panning out to take a chance on McQueen being a long term project. McQueen possesses top-3 talent. His back injury is different from Lindstom's, which has been said to be normal for some kids who spiked up in height/weight. What is positive for McQueen is that he was able to return at the end of the season, but had back problems again. He is listed at 6'5 and 192 lbs, which means his body has grown out faster than his body can adapt. For reference, Sennecke was 6'3 and 192 last season.
The question to ask is are the other talents top-10 worthy or are they 3C/ #4D. This is a weak draft. Like you surmised, it's gonna be a tough decision.