Your itinerary sounds good and interesting and in 10 days you have plenty of time to explore the area.
Regarding travel by ferry from Vis to Hvar note that at the present, there are ferries between these two ports only once a week, on Tuesdays. On any other day you have to take ferry to Split and then from Split to anywhere else like Hvar, Mljet or any other island.
Hvar, Mljet and Korcula are well connected by daily ferries to Dubrovnik while Vis is not.
Interesting itinerary and enough time to see everything. If you like nature choose Mljet national park if you like night-life choose Hvar, if you like both choose Korcula. Or all of them for night or two. Allow 2-3 days in Dubrovnik for easy sightseeing.