Yeah I think the Bronx has a higher chance of being gentrified...much of Queens has an "outskirts" feel to it so I don't think Hipsters would care much for it
It's definiely the Concouse area near 149th that's likely to start first. It has the perfect setting for hipster appeal.
But it's gonna be much harder to gentify the bororugh compared to Brooklyn. Brooklyn and Queens have shorter and easy access to Midtown and Downtown which is desirable. Bronx on the other hand can easily take from 30 min to an hour, and even in the South, you would still have to go all the way through Harlem and Central Park to even get to Midtown/Downtown.