LOL. This is like watching a game of Werewolf... Folks pretending they "know" who a wolf is then voting to get rid of someone that turns out was a villager.
Anyway... Thomas's "crazy wife" would have leaked more than just this decision over the time he's been there if she was the source. I do not believe you are right about whether she is crazy and leaked it, or that someone in his staff was the leak. It is far more likely someone newly around SCOTUS decisions decided to leak it for their own purposes. Of course they didn't leak a more recent version, probably because later versions don't sound like it at all and may not even overturn the two cases (Roe and Casey, not just Roe) entirely.
If there are later versions, then we could find out that the first draft was thrown in the trash in which case it could have been a janitor or a worker for the company hired to shred documents. The copy doesn't have a date so we don't know when it was sent.
You sure this isn't more like a game of Secret Hitler as opposed to Werewolf?