On the avatar thing, I've checked my replacement variables, and I've got src="customavatars/ being replaced with src="$vbulletin->options['bburl']/customavatars/, so I see no reason why some groups aren't doing that! Ugh.
***UPDATE***
I found the common thread between the groups that don't show custom avatars! If the group leader does not have an avatar, those with avatars won't show properly. If the group leader DOES have an avatar, then everyone else's avatars show properly. Hopefully that's enough enough to get it fixed!

No matter what the group leader's avatar situation is, users without avatars correctly show the noavatar.gif image.