As yaff80 mentioned, dipping finger could be to remind us of ???? ?????, another idea is “????? ????? ?? ????”- with the fall of your enemies do not rejoice, and so to show a little sadness at the fall of the Egyptians we pour out a little wine in their memory. (This 2nd ??? is, admittedly, not so good, because the Gemara in Megilla says that this only applies by other Jews ??”?).
As for 147, I believe that the idea of pointing the pinky at the torah is that as we find many times in ??”?, when we say “????” or similar words, it means that someone is pointing at it (ex. ???? ??? ???, where Rashi explains that Hashem showed Moshe how the moon is supposed to look) so we point. As for why the pinky, Rav Belsky said that the “pointer” finger is an accusatory finger, so we do not want to use that, and in addition the pinky seems to be a “humble” finger, so to speak. Whatever the real ???? is, remember “???? ????? ????” and “?? ????? ?? ?????”.
Oh yeah, and ??? ??? ???.