I'd like thoughts on this. Say your Sorcerer takes one of the feats that allows them to cast Find familiar. If you cast a spell with a range of Touch and Twin Cast it, is the familiar able to deliver both spells simultaneously? 

A related metamagic question: if you have a Touch spell but use Distant Spell metamagic, can the familiar effectively make a ranged attack? 

I'd say yes to the first one, no to the second. As long as the range is still touch, you can cast it through the familiar.

That's pretty much what I'm thinking, as well.