Eilistraee.com

What is Eilistraee and Selune's relationship? I've read they are allies, but little about them interacting. But I'm fairly new to Forgotten Realms, I've played NWN, but never really got into the lore until recently with BG3.

I do think Eilistraee would be so totally proud of Isobel and Aylin.

But are there canon interactions?

There isn't much that I know. Ed Greenwood once says that Eilistraee, Selune, and Mielikki sometimes spend time together, and her followers in Velarswood often celebrate holy rituals alongside the Selune-worshipping lycanthropes there.

You might have better luck asking directly Ed, on his twitter (@TheEdverse).