Hey there,
This article might be helpful to answer some of your questions: https://wiki.nwnarelith.com/Playing_any_UD_race
1) While you can go into a Surface settlement (with enough bluff/perform) to pretend to be an Elf, it is massively dangerous and no Drow should really linger in a Surface settlement. There are those who would brave getting into Cordor to read the public board or check the shops, maybe break into a quarter if you have the skills. But you shouldn't really hang around the fire chatting with the locals for example.
2) You need to ensure you have OOC consent. It's common courtesy at least to figure out if someone wants to be a slave before you drag them to the clamper. Taking slaves requires a lot of kindness and patience and checking to ensure that the other players are having fun and are comfortable with the situation.
3) You really don't want to be out during the day as a Drow. Those debuffs are nasty and your sun sensitivity should truly reflect in your roleplay. Don't be on the surface during the day really, it would hurt too much.
4) Drow are quite politically minded. Their wish is basically to be at the top of the food chain. If a Drow can use another race (for example a large powerful/influential Kobold clan) to help further themselves politically in Andunor they absolutely would "get along". If they see a group of strong Gnolls, they might wish to be nice so they can use them to do bad things. Like anything, the more good relationships you have, the stronger you are really. But they absolutely plot and scheme. They're out for themselves ultimately or their Matron. Know that a male Drow is beneath a female Drow in the hierarchy.
5) If you are going to focus on capturing slaves, I would find likeminded individuals in the UD. Ideally you don't go hunting writ workers constantly (it gets old real fast), but you try to create a fun and engaging story that isn't just centered on PVP. You could start as a Houseless Drow and then join a House you like, you could serve in the Temple of Lolth as a Killian, or if you have friends who play in the UD and have a Drow House you could make a member of that House. Just keep in mind Drow are backstabbing, cruel creatures (by and large anyway) who hunger for power. That might be a good start?