It's a stretch to assume they all hit the ground running. Guerrero is the only one I can safely assume will be at least an above average hitter at the MLB level from the get go.
Absolutely not.
Diaz would be on 2nd with 2 out. Generally if your name isn't Kendrys or Justin you're going to score on a hit to the outfield. Add in the fact that McAllister had no control, it's a terrible decision to make.