oomis,
I don’t think you’re disagreeing with pba about inventing new rituals, but I think you are being a little naive when it comes to (some) peoples motives for creating certain ones. The Chasam Sofer forbade a chuppah in a shul, although it was inherently muttar (the German Jews did it) because it was stressed by the reform, to imitate the notzrim.
Simchat bat, I believe, was invented (or at least applied by those who don’t really have that minhag) for the wrong reasons.
BTW, I believe that throwing something by an aufruf (although I think it used to be raisins and nuts) is a real minhag, but it is a more recent innovation to do it at a bar mitzvah as well.
Oh, and you could have made a kiddush the week after your daughters’ birth, as many people do.