It does look like they'll be aiming for full voice acting for custom characters. It was mentioned in the AMA they did on Reddit a while ago, so unless something has changed since then it should still be the case. That said we have to keep in mind that the game is still early in development, and plans change. There's also no guarantee that they'll have it in Early Access if they do.
Here's the relevant bit from the AMA for reference:
Will custom (non origin) characters have Voice Acting, or is it for for origin characters only?
Adam: Hello! Yes, custom characters will have voice acting - you’ll choose a voice as part of character creation.
That's the real question. An answer like Adams is technically correct but doesn't get at what we're looking for - will lines be voiced etc. in similar ways for origin vs. non.
We get they'll have voice lines... that's basic.
Adam: They'll have full voice acting, just like origins!
Link to the compiled AMA if you want to check anything else:
https://www.reddit.com/r/baldursgate/comments/fhq9cq/compiled_baldurs_gate_ama_20200313/
Last edited by DarkSeldarine; 27/06/20 06:48 AM. Reason: Sorry, my Stranger status appears to have made the formatting ugly. Removing formatting for the time being.