Hi,
I am not sure how BuddyPress separates that – but there are options to exclude users by the roles, in case the profile type is a role. If the profile type is somewhere stored as user metadata, then using a hidden custom field filters on user meta could aslo work to only include those matching the criteria.
The autocomplete is currently avaialble for the Posts, tags, categories, other taxonomies, statistics database, google places API and google. I can however take this up to the requests list, it should not be too difficult to add in a future release.