DaasYochid:see Tur 268 and Shulchan Aruch 268, se-if 2.Virtually same “loshon” as Rambam,with Bais Din being outside of room until the actual tevilah.I don’t know what Rabbi Lipman said contrary.
Sam2:when it comes to “bedieved” you absolutely can rely upon Makilim, even if they have many others arraigned against them.And you are minimizing Rav Uziel’s stature by dismissing him summarily.