LOL.
about party lock - initially, it was the plan. they were very clear about it. but after a while, we got a comment from one of the developers (I think it was during some Q&A on reddit) that they are reconsidering it. So we can't know for sure

Larian's Biggest Oversight, what to do about it, and My personal review of BG3 EA
"74.85% of you stood with the Tieflings, and 25.15% of you sided with Minthara. Good outweighs evil, it seems."