not sure I really understand the use case for hiding the usergroup memberships, but doesnt really matter... our themes are very much like WP themes... everything displayed is controlled by template functions... you have complete control over what is display or not displayed...
so you just need to qualify the display of usergroup info int he topic view template file...
but first, I really need to ask for clarification... when you say author box, are you referring to the author info section to the right (in most themes) of topic posts??? or other? do you mean the profile?
as with WP themes, in SP themes you have complete control over what is displayed or not via the template files and the functions within...
of course, before making any sp theme mods, you really should make a child theme or a custom theme...
for example in your sp theme, look for this (assuming you meant profile):
sp_UserMembership('', $spProfileUser->memberships);
to only display for admins and mods, change to
if ($spThisUser->admin || $spThisUser->moderator) sp_UserMembership('', $spProfileUser->memberships);
and it will only be displayed to admins and mods... this example is from reboot, but applies to other themes that display it... worth noting, its also for the profile popup template file... you may want the same change for the profile display template file...
The members list you mention is a bit more problematic.. and needs more questions and understanding...
do you even want to show a members list?? normally, its organized by usergroup... if you dont want folks to know memberships, may make more sense to just remove the members list... we can help if that is what you really want to do...
if you just want a singular list of members, you might look in your members view template for this line
if (sp_has_member_groups('usergroup', 'id', 'asc', 15, true)) {
and change it to
if (sp_has_member_groups('user', 'id', 'asc', 15, true)) {
and see if that gives you what you want...