I am running FreeHand 10 in Snow Leopard server via Parallels 8. It is working very well for me.
I have a 2013 iMac running Mountain Lion. I understand that someone else on here is running Yosemite successfully! I don't plan to change right away because I would also have to upgrade parallels and possible Snow Leopard server. Speed is not a great need for me so I am thinking, "If it ain't broken don't fix it!"
I posted this in case it might be of help to someone else on here.