Few questions.

[Lynne]

Find these lines in FORUMHOME:

                 $vbphrase[members]: $numbermembers<if condition="$show['activemembers']">,
                    <span title="<phrase 1="$vboptions[activememberdays]">$vbphrase[within_the_last_x_days]</phrase>">$vbphrase[active_members]: $activemembers</span>
                </if>

and change it to:

                 $vbphrase[members]: $numbermembers<if condition="$show['activemembers']"><if condition="!is_member_of($bbuserinfo, array(x,y,z))">,
                    <span title="<phrase 1="$vboptions[activememberdays]">$vbphrase[within_the_last_x_days]</phrase>">$vbphrase[active_members]: $activemembers</span>
                </if></if>

where x.y.z are the usergroupids of the groups you do want to see Active Members.

As for profile fields in postbit, see this article: How To Add Custom Profile Field Information To The Postbit