I have an attachment with a stud that came with my Frezzi light that slides into the shoe of my DVX100. Can I use it with the A1 or will it short out something in the hotshoe?

The XH camera does not have a hot shoe. It has a cold shoe. There are electrical contacts for communicating with an EOS Speedlite photo flash but that's it. I don't think you have to worry about shorting those out.