Is there a way to light up a blf is someone is in a queue slot - This could be done, but it's not available code base that I'm aware of. I think there are some caveats that would make this feature tricky to write.
is there a way for internal calls to be presented before a queue call if call waiting is turned off - I'm recoiling at the thought of even considering the lua script that you would need for this feature as described. You could possibly give them a queue extension and an internal extension on their phones.