If I'm reading the description correctly, can I pick and choose which maids get nsfw and which stay sfw or is it all or nothing? For example, if one of the later maids I get catches my interest and I want her to not do anything nsfw, can I just not let her and romance her myself?
Yes, you can control each maid's lewdness towards you and clients. You can set up so one girl will be into sharing while other will be only for you. You can even tell her to stop after you will see some sharing already or after all you will want to share this maid. I plan to have it all represented in some way in the final endings.
You have to give each character specific item (triangle pin) to tell them you are okay with sharing them. There are also events where you have to give your permission for sharing (simple yes or no).
hope it helps