The truth, or part of the truth, about Obama's college records may be that there really aren't any substantial college records for Obama to hide.
Without records what proof is there that he actually college full time or that he graduated at all?
Regarding his father - I doubt Barack Obama Sr. is really his biological father and I doubt that Obama Jr. himself even knows the identity of his real father with any degree of certainty.
He no doubt has some suspicions though, and his mother probably could have worked up a short list of half dozen or so of the most likely candidates.
He didn’t attend any classes at all in Columbia his “junior year” because he was on the other side of the globe helping Prof. Brzezinski set up Al-Qaeda in Af-Pak. A deal had been cut and the skids had been greased to get him a diploma. Any classes he was registered in his senior year would have been pass/fail or audits that he just attended when he felt like it.