He said he missed weightlifting once. Can we recall what he did instead? What was it?

This is pretty crucial, since we don't know what would fill up the day. It doesn't necessarily need to have been the party, but the purpose of the question would be to see if he can highlight the reasons for why he missed something he did every single day.

If he can remember, it would be consistent with the idea that the event had to be one that was very uncommon or unexpected. If not, then that could be an indicator that it had to be an activity he did often.

He said he would often have too many beers, but didn't know how many that was. Wouldn't that necessarily mean that he would have to recognize that he was drunk, while he was drunk?

It would be an interesting answer here. If he is able to answer, you could follow up with the question of what he was like when he was drunk — and detect if the answer is behaviorally consistent or if is suspiciously off.

He would have to have had to have some level of gaps the day after to detect that he was drunk the night before.

He called the Swetnick accusation a joke but didn't want to respond. Is that because he believes it is irrelevant or absurd?

The answer here could tell us what he personally believes his behavior matches best with. The answer here can't be great reasoning for whether or not he committed assault, but rather, would tell us how he personally deems his own behavior.

He openly declared that he was shy about his sexual inexperience. In order to cover that, did he ever feel like he attempted to appear more sexual than he actually was?

The answer here is important for pretty self-evident reasons. It would tell us whether or not he is the type of person who instinctively feels a greater need to be accepted by those around him, or if he is confident in the skin he wears. It could also help determine a hypothesis about his general behavior in accordance to the people he hung out with.