It depends on your need. These players offer very different things. Profar is probably the top prospect in baseball right now, but some of that is tied up in defensive ability and age-relative-to-level, none of which matters for fantasy. In Profar you're looking not looking at someone who's going to hit 35 HR, but what you could have is Elvis Andrus with pop.
With Myers, you have big-time contact ability and power. He could be that 30/100 #1 OF in the mold of, say, Jay Bruce with a better average.
Hamilton is a little further away from a starting gig and it's not clear exactly where he ends up, SS, 2B or CF. Smart money is on CF. He's category domination in a glass. He just broke the all-time minors record for steals in a season. He's the fastest man in baseball; routinely scoring from second on sac-flies. He could end up stealing 100 bags per season, IF he hits well enough to get on base. He's taken a big step forward this year but his bat isn't in the same class as Profar's or Myers'.
Personally, if I'm only taking one guy, it's Profar. Myers could end up having more gaudy HR totals and Hamilton SB totals but Profar plays short; SS with his skillset simply do not come along very often. His plate discipline and contact ability are almost unheard of for his age.