Think that through, and you'll see the error.
The law automatically says, "didn't do anything wrong" on AJ and William's account. The presumption of innocence does that for them.
So what bit of "story" could they possibly add that would help the jurors disbelieve the accusation?
The entire second-by-second story is already out. There are variations on the theme (was the friend in the room or not when AJ+accuser began having sex? did it start with this particular sexual activity, or that? did he put on a condom at this point, or that?), but none of that is important, at the end of the day. There is only this: do you find the accuser credible?
If you have your clients testify, now the jury also has to decide, "do you find the defendants credible?" The risk increases.
So, no, I doubt you'll ever hear any story from AJ or Williams.
p.s. Thinking about it a bit, game theory may actually conclude it's better to introduce a "defense story." Follow me on this:
If there is no defense testimony, the jury has two possible positions: she's truthful (guilty) or she's lying (innocent). 50/50 chance for the defendants.
But if the defense offers their own story, the jury can now reach four conclusions: (a) both accuser and defendants were credible (tie goes to the defense=innocent), (b) the accuser was credible, but not the defendants (guilty), (c) the defendants were credible, but not the accuser (innocent), or (d) neither the accuser nor the defendants were credible (tie goes to the defense=innocent). Which == 75% chance of an innocent ruling for the defense.
So...contrary to the old rule to never put the defendant on the stand in cases like this, maybe game theory proves that you should?
I don't know. Would love to find out whether any lawyers have ever studied defense strategy in this way.
While your theory tends to be sound, the way juries work is far more uncertain. Jurors are regularly told that they cannot consider a defendant's refusal to testify as evidence of guilt, and that the state has to prove guilt beyond a reasonable doubt. But many jurors subconsciously ignore that instruction. Subconsciously, they think if the defendant was innocent he would have testified.
Here, just looking at the testimony in the trial, the downside risk to putting AJ on the stand seems relatively low. The biggest problem a witness faces is inconsistent testimony--they say something earlier that turns out to be true and they are caught in a lie they have to explain. The closest thing here seems to be the accuser's statement that she didn't want them to be arrested. It doesn't look like they have caught AJ in anything so you really don't have a good hook to cross examine him on.
Also, remember there are three potential outcomes--guilty, not guilty, or hung jury. Two of those favor the defendants. If AJ testifies well, he doesn't have to convince 12 jurors he didn't do it. He just has to convince one or more jurors strong enough to hold out for acquittal and he walks--at least until a second trial.