I've seen your messages on Disney Wiki and Community Central regarding the whole ordeal with the deluge of edits you've made here recently. First of all, I apologize for the stresses caused by my handling of the situation. Seeing that many edits by one user who has just recently joined this wiki tends to be a wake-up call for us admins (especially since GrayWolf2 and I are the only relatively active ones on here), and it was especially startling seeing such massive changes to the more established articles.
Let's take on these things one at a time.
First, Yin. That one I had to take care of right away since in her case official Disney media did confirm her gender, as you have noticed by now. But yes, to reiterate this anyway, there was an event in the mobile game Disney Tsum Tsum that finally gave us a definitive answer regarding her gender, which was an issue after all these years. (Also, to get this aside, the game is actually very popular. It's more popular in its native Japan, but there is a decently-sized dedicated community of non-Japanese players, with an active Fandom wiki and an active subreddit. It doesn't get much mainstream attention here in West, but that doesn't make it "very obscure".) When I saw those edits you made, I had to make sure that the information was clarified to avoid further confusion.
Second, Shush. Now part of the rollbacks for that experiment's article were related to seeing Yin's article edits. In other words, it was a kneejerk reaction based on related events. You are right though in that there isn't any other evidence regarding that experiment's gender; in fact, I've played through the whole Tsum Tsum event that I mentioned and never saw Shush in the event myself. So as far as we know, Shush's debut really is all we got when it comes to information.
Part of the whole issue with the spread of different information about the experiments may be related how there was a lot of activity and discussion relating to the franchise back in its heyday in the 2000s compared to today where the franchise has fallen out of favor as fans moved on. Changes in the Internet and various websites over the years have also caused some of the issues; back in the time of The Series, Jess Winfield held a thread on TV Tome answering fans question about the show, both regarding production and in-universe material. After The Series ended, TV Tome eventually became TV.com, TV.com changed up the community boards, and Winfield's thread ended up getting deleted from the Internet. The only known archive that exists today is a New Zealand fan's upload of the thread's first four pages, and they claimed that their personal archive also had pages 5 to 27, but their hard drive that contained their archive failed and they couldn't afford to get the thing repaired. The fan's archive hasn't been updated since. The official website for The Series itself has also been deleted due to Disney's changes to their websites and the show having ended production since.
Another thing is that the production of animated TV series, especially during the time The Series was made, isn't perfect either. Sometimes, there are animation issues (e.g. Reuben being drawn with four toes instead of his normal three). Sometimes, the plot contradicts past events or information in the show's canon (e.g. Experiment 033 appearing in "The Asteroid" as "Hammerhead" as part of the 'ohana, but gets activated, trained, and named "Hammerface" by Gantu in "Dupe", which aired later). And sometimes, the scriptwriters mess up and give out inconsistent or contradictory information to the voice cast and/or production crew (e.g. All the instances of experiments being referred to by the wrong numbers in a few epsiodes). Winfield was likely aware of this and answered these problems on his old thread, but again, it's mostly lost. I will mention that Winfield is active on Twitter and he might answer some fans' questions (if asked politely) about the show and the franchise; I've seen comments on the web where some fans stated they asked him questions about things in the franchise and he did respond to them. Note though that one, he's busy with his life like anyone else (so don't pester him), two, he doesn't really talk about Lilo & Stitch publicly on his account (he typically responds only with private messages, which means that fans have to share these messages themselves on their Twitter accounts), and three, he is very politically active over there (although he keeps politics out of his L&S messages, if politics are too much for you to handle, then you might want to steer clear of reading what he has to say).
One more factor is that, sadly, everyone's memories are faulty, mine included. I have been trying to rewatch the entire run of The Series in airing order lately to refresh my memory and improve the accuracy of information here. (e.g. I found out from rewatching "Kixx" that the name of outdoor gym on Lahui Beach is actually named Muscle Bay thanks to a TV broadcast that Lilo and Stitch overhear, so I took care of that as soon as I could.) However, my life have been getting in the way of me doing my binge watching; I'm so behind that I've only just recently finished "Splodyhead" in the past couple weeks. In fact, as of this message, I'm going to be busy with my real-life job for the next couple days, so I'm going to have minimal time on my computer until this Saturday at the soonest.
With all that said, I might consider changing the pronouns in Shush to gender-neutral ones (i.e., they, their, and the like) and change the trivia bullet point to something like, "Lilo and Pleakley referred to Shush as a male in their debut, but they are often considered to be female by fans." but stop short of making a declaration over their gender until further notice.