Boccob vs. Nethys vs. Mystra

[ShurikVch]

Corellon does have the Magic portfolio, but not the domain

Check the Faiths and Pantheons - yes, he have Magic domain!

Isis and Girru are from Egyptian and Sumerian pantheons, both of which use a form of opposed pantheon structure, rather from a WotC published realm and pantheon.

Once again, Faiths and Pantheons - Isis is there (under the "Mulhorandi Pantheon")

More like she gives them power outlets instead of lightning bolts.

Lightning bolts are completely unusable for any practical means
"Most spellcasters instead draw upon magic through the controlled and relatively safe magic accessed through the Weave" means some of spellcasters, actually, don't draw upon magic through the Weave, and instead using raw magic (regardless of how difficult or dangerous it may be)