You mentioned something about one of them being a PI - I think that could be a good angle. Gus will DEFINITELY be trying to put a case together against Bastian, so he'd be trying to use any resources available. Just as a random sort of tangent, I'm thinking he goes on runs every morning before work, so maybe one of those ladies wound up being a jogging buddy? I'll probably come up with more stuff after I've played him a bit.