I do agree with a lot of points you make. I found it odd in reverse when my Llothsworn Drow had no option other than something good. I can't remember the scene offhand, but the point is that if you aren't going to have players select an alignment then you need to give them all alignment options in dialogue regardless of race and such so that if Im playing an evil Drow I can be evil all the time but if Im a good Drow I can be good all the time. I mean, like you said, some exceptions apply, of course. Lae'zel, for example, should be friendlier to other Gith and have different dialogue options. That kind of thing.
I actually think itd be better for Larian if they'd just did make alignment part of creation so it limited your particular character's dialogue choices. Wouldn't that be easier than trying to make sure all dialogue options were available for all characters?
Either way, I also think deity should be a choice at creation for all characters. Not a race choice but deity choice. Heck, choosing deity could be used to determine alignment. I choose to be a follower of Tyr. That makes me Lawful Good. I follow Eilestree, that makes me Chaotic Good. I follow Loviatar, etc. If you pick None, for deity, you are Neutral. Make that the tag that directs most dialogues with race only directing a few.