The remaining regexp glitches found by the latest sweep were fixed by the attached patch (now on master), except tramp-adb-prompt:

lisp/net/tramp-adb.el:59:56: In tramp-adb-prompt: Repetition subsumes preceding repetition (pos 50)
  "^[[:digit:]]*|?[[:alnum:]\e;[]*@?[[:alnum:]]*[^#\\$]*[#\\$][[:space:]]"
   ....................................................^

I think it should be "^[^#$\n]*[#$] ", but hold out for some assistance from the author (Jürgen Hötzel, contacted).