If you want to count the returned rows from the two subqueries, how about this:
SELECT 'Query1' as which, count(*) as cnt
FROM ava_friend_requests
LEFT JOIN ava_users
ON ava_friend_requests.from_user = ava_users.id
WHERE ava_friend_requests.to_user = $user[id]
UNION ALL
SELECT 'Query2', count(*)
FROM ava_friends
LEFT JOIN ava_users
ON ava_friends.user2 = ava_users.id
WHERE ava_friends.user1 = $user[id];
EDIT:
To do this after the limit, make the current query a subquery and do the counting:
select ord, count(*) as cnt
from (SELECT ava_users.*, 0 AS ord
FROM ava_friend_requests
LEFT JOIN ava_users
ON ava_friend_requests.from_user = ava_users.id
WHERE ava_friend_requests.to_user = $user[id]
UNION ALL
SELECT ava_users.*, 1 AS ord
FROM ava_friends
LEFT JOIN ava_users
ON ava_friends.user2 = ava_users.id
WHERE ava_friends.user1 = $user[id]
ORDER BY ord
LIMIT $from, $display_num
) t
group by ord;
It also might be easier just to count the ord
column at the application level.