Can I rent hockey skates or am I going to get some sort of joke figure skates?
All the rinks mentioned above including Ice Vault have both kinds to rent.
Other than a couple of figure skaters practicing, you should have most of the ice to yourself if you go during the week as opposed to the weekends.
I also checked the Floyd Hall website. They have High School open hockey tonight 11:00 PM and Saturday night 9:50 PM. Be sure to bring both a dark and light jersey if you go.
Go to a couple public skating sessions to get comfortable skating on the ice, which is what you are planning to do now.
I'd skip the clinics and just go to the open sessions, especially since you are already accustomed to the game. I've seen so many roller hockey players make the transition from roller to ice and feel incredibly comfortable after just attending one 90 minute open hockey session.