Unpopular opinion, but multiclassing giving access to powerful main class passives should not be a thing
It literally doesn't matter the slightest bit.
If you make a companion or hireling with 8-10 sorc / 2 wiz / optional 2 cleric, you only get 2 feats.
You cannot have 20 caster stat and elemental adept which you can with 3 feats on a pure sorc hireling / companion.
And I still can't find any lightning bolt scrolls in Act 3, all the vendors only sell level 5-6 scrolls now so I can't try it out.
Even if I tried it on my MC - 1 feat for +2 CHA, 1 feat for Elemental Adept: lightning, no more dual wield staffs because no third feat.