Sam2, Your first point has some validity, (I’ll get to that soon), but the last two are based on ignorance of basic Shulchan Aruch.
The halachos of hataras nedarim are in Y.D. 228. In siman 1, he says that if there are three people, they need not be “mumchim”, they can be “hedyotos”. Definition (Taz and Shach): needs to be capable of understanding, but doesn’t need to already know.
In siman 3, he allows relatives.
In siman 14, he does say that the neder needs to be specified. The reasons, however (see Taz) are based on the possibility that had he specified, the dayanim may not have been matir. We specify, though, that such nedarim are not included.
There are also a number of shittos which argue on the S.A. who says that hatarah without being m’faret doesn’t work b’dieved; they hold it does.
Our hataras nedarim is valid.