Hi @edwin, sorry for late answering. I'm traveling these days.
1) It's not decided yet. The bottom line is that we accept a new order only after we deliver all the existing Unicorn orders.
2) N/A, since it's not open for sale at the moment.
3) Sorry, it's not a (semi) custom build, so you can't choose the cassette type.
4) It is referring an adapter that you could turn the internal routing to external routing. Both of the Leopard and Unicorn are full internal routing. Sleek, but unfriendly for mechanics. So some riders want to change to external routing.