Gendered Pronouns for Privacy-Masked Individuals

Solution 1:

I see no need to eliminate gender from the pronouns, since the gender was already revealed.

There is a reason not to eliminate gender from the pronouns: it makes the text harder to follow.

Why tie yourself up in knots if it's not needed?

On the other hand, if you don't want to reveal a user's gender to the readers, then don't disclose it in the first place.

Solution 2:

If it bothers you to use he and may bother your readers to see they, it's a formal paper so you can always go legalistic on it:

User 1 (hereinafter "1") posted updates 5 times in Foo, but only when talking about bars. 1 does not seem to like bars very much, so this choice may indicate 1's distaste for the Foo language.

The reasoning there is incredibly spotty. It's much more likely that terms of abuse are rendered in the beloved local dialect than in the prestige dialect used elsewhere. The formatting should be fine for the pronoun conscious, though.

Alternatively, you can use capital letters in place of numbers, if that might cause trouble in the paper.