The question is a moot point. The USGA currently does not even contest US Amateurs on non US-Open worthy courses, hence this years contest at Chambers Bay 5 years prior to the US Open. Until they change that policy (I haven't heard of that publicly), the US Open will not be awarded to BDGR. As for the PGA, I seriously doubt they would put BDGR on their radar for the obvious logistical issues (hotel space / distance from major city).
To the question which course could challenge the pro's, all of them would provide a stern test, but their preoccupation with yardage would probably limit them to Old Mac and Bandon Dunes. Pac can't get past 6,900 and Trails the same. Old Mac at 7,000 / par 71 and Bandon over 7,200 / par 72 are both sufficient tests for the pro's with Bandon summer weather.
Having said all that, I'd REALLY like to see Tiger and the boys play the finishing stretch at Trails. My hunch is they'd be sufficiently challenged, and with 3 played as a par 4 / total par 70 it may be the best test of all of them.