Doom:
You wrote: “Rav Shmuel shlitah said that Yeshivas/BY may not stop unvaccinated children from attending Yeshiva/BY.
You don’t consider that an anti-vax position?”
Rav Shmuel shlit”a specified that this was not during an outbreak. If you don’t believe, ask him.
Rav Shmuel was not pro-vax. But he was not anti-vax either. Review direct quotes from him. His Rebbetzin was anti-vax. No idea whether she changed her mind, or thinks differently during an outbreak.