I think it's going to be a crap shoot no matter which way it goes, really. They might be fine, heck - I've heard of people keeping dwarf angels and seahorses together - in theory it shouldn't work
The biggest issue I can see is that you're going to have one very calm, passive and thoughtful fish. Then you're going to have an ADHD fish that might pester the heck out of your Mandarin. And with most mandarins being picky eaters, it might not be the best situation, and you may end up with a very, very hungry mandarin.