I suspect the truth, like for most questions related to the future of minor leaguers, lies beyond stats an instead can only be explained through first hand observations by those with that type of skill. In other words, delving into the statistical history of three guys with parallel paths seems like it might be illustrative, but it just produces noise, especially if you threw Altuve into the mix.
Alternatively, there are most likely Astros player development people, or scouts, who could provide meaningful explanations of Clemen's and Gaston's success at Lancaster and their subsequent difficulties at higher levels. Probably something about the nature of their weaknesses and the strength of AA and AAA pitching. Maybe they feel there is a similar flaw with Hinze, and don't see his promotion, or lack of promotion as that big of a deal. Then again, maybe he is promoted tonight, rakes in AA and eventually becomes a solid MLB player.