Deleted user, now how to delete posts?

[Urinemachine]

Hello - I deleted a user and their name says guest under it now, which is good. But, their posts still show.

Can I delete their posts somehow in a graceful manner? I could do a SQL query and just start dropping things but I think that'd get hairy.

Also, can I delete their posts even if they're the original poster (thread starter) and still have their thread remain? IE - make the 2nd post the first post of the thread since the user I want to delete will be removed?

Thanks all