The videos got blocked on the GB player but as far as I know there is no way for a GBA game to tell what region it might be running on.
The DS did also see a region lock for the ique games (a China only model of DS), and technically a few games carried translations but were not active in the game (most notably one of the Advance Wars titles had Japanese onboard but did not come out in Japan but there were others).
But yes as far as I know the DS original and GBA SP both use the same 5.2V output charger, not sure what the official ones can take as inputs but that is a different matter. I certainly charged my NA GBA SP using a charger I got with my EU DS original, and said SP's charger when I went back to the US with my DS.