Then there are the Torchwood and NuWho complications of the Tardii being spaceborne coral creatures carved for use.
Uhh... no. Sorry for airing a pet peeve, but I get tired of the affectation of using "-ii" as a mock-Latin plural for totally inappropriate words. "Tardii" could only work as the plural of "Tardius" (because the actual plural of "-us" is simply "-i" and there's only a second "i" if it's part of the root, as in radius/radii). The "-is" suffix is Greek, not Latin, so if "Tardis" were a Greek word rather than an English acronym, the appropriate fake plural would be "Tardes." (Cf. analysis/analyses.)