For future reference,
First, the query to get userid must return a flat array, not a nested one. You must use qa_db_read_all_values(qa_db_query_sub()). In the future 1.9 version, the core developers may change this.
To list the items, you can use this to list the first 3 values, the rest can be expressed as "and # others",
list($first, $second, $third) = $userids;
echo $first. ' '. $second.' '.$third. 'have answered this question';
That's why you need a flat array, not nested.
To return the username, use this Q2A function, which is missing from official DOCS.
- qa_userid_to_handle($first)
- qa_userid_to_handle($second)
- qa_userid_to_handle($third)
Similarly, to display avatars, you do MySQL queries, or exploit the Q2A functions to return avatars from $handle (ie, username).