Going from memory here, but restoring the fire handle to the normal position re-opens (or at least re-enables) everything that was isolated when the fire handle was pulled.
I know that the fuel valves will reopen, not absolutely sure about bleed and hydraulics. There was a rather infamous incident years ago on the Boeing flight line where, after a pre-delivery check flight, the operator pilot shutdown all four engines on a 747-400 via the fire handles. Problem was, he then restored the fire handles without setting the fuel control switches to cutoff, which reintroduced fuel into still hot engines as they were still spooling down. Massive tailpipe fires and major turbine damage was the result. Whoops...