What happened to the other characters?
Colonel Dwizok or Oncle Piotr as he was known to young Friedrich had survived the wars only to die in an uprising against the Russian occupation.
Lieutenant Blanc Returned to France and was employed in the ministry of war up until the Peace of Amiens when he retired and opened a restaurant that has done well ever since.
On repatriation Captain Twyth returned to the hussars, rising to command of his regiment and then commanding a brigade. He was killed in Russia leading his cuirassiers at Borodino.
Baron Wilhelm fled to Austria after the French finally occupied the Frei Stadt. After the Austrian defeat in 1809 he moved to Prussia, helped with raising a Frundsberg Freikops in 1813 and then returned in 1814. He then settled into retirement at his manor at Altfeld just outside Sonnenbad.
Franz Ferdinand was demoted back to head of the serving staff with the return of the Pommaine nobility but was appointed burgermeister by the new Westphalian regime and somehow kept his position after the provinces moved into Prussian control.
As for the glorious volunteer Freihussaren and the others, who can say?