Warning! Potential spoilers ahead.
“I have been told that in the untitled young Han Solo story there is a character named Mother Proxima. Apparently the character is likely some sort of puppet. The character is operated by Dave Chapman. Chapman is known to the Star Wars crowd as the one of the two BB-8 operators from The Force Awakens. There is always a chance Chapman is operating the character but Mother Proxima will be voiced by one of the actors we’ve heard that has been cast in the film.
On the latest episode of Now, This is Podcasting! we also discussed another character with top billing named Val:
There is a female character in the untitled Han Solo story that is named Val. I have now received several reports that the name “Val” was used at Pinewood and that Val had some sequence involving stunts so there will be action around this character. The strangeness of the situation is that that no one will confirm who Val is to me at this point. […]”
Source : MakingStarWars.net