Picking a clean up crew is easy, talk to Jeff over at Reefcleaners.org
Most of your stock list looks okay to me, but you definitely cant keep that whole list of fish in a 75 gallon (but it sounds like you already knew that)
I'd advise waiting at least a good 6-8 months before adding a mandarin - you're going to want an established pod population before adding one
You many also have issues with two jawfish in a tank that size