I think longspear is actually a pretty good weapon, actually. Kinda low base damage, but after a while that doesn't matter much anyway. It gives you the reach and set vs. charge, and a decent crit (x3)...can't really ask for more from a simple weapon.
Good points.
For heritage feats...I'd say go fey heritage or none at all. Fey seems pretty good, and you have plenty of other feat options. I guess draconic could work solely because of the sorcerer side.
The thing about Draconic Heritage is that they really pandered to the dracophiles out there- it has the broadest selection of Feats of any of the Heritage feats, and many of them are useful. Beyond the Draconic Breath & Practical Metamagic, other feats give you flight, natural AC, Fear aura effects, and some even have a "per Draconic Feat" elements to them.
The main problem, of course, is that to get the most out of them, you need to commit to them...and like all non-Fighter classes, you're starved for feats.