Tell us about yourself!
Ever seen a sign saying "High Voltage - perfectly safe to touch"?
Not unless you can pulse the DC input.
AC will throw you off, DC will induce spasm and prevent you from letting go of the source.
Not really, flybacks are sort of fickle that way. I'm fairly sure they work off a resonance and don't like to be used any way but their designed operation. A microwave oven transformer would probably suit your requirements better. They're also much easier to change the windings too.
Agreed, this chap may not be 100% on what he's talking about...