I don't sit with the answer, but I could chime in with some thoughts. First, it's a bad day the at the office with G+Y HYD failure and SLATS LOCKED. Never heard about it happening but could possibly be the result of hitting something hard..? My major concern would be stopping distance, having only brake accumulator pressure and landing with a clean wing.
I personally think the whole ECAM checklist system works OK with simple, isolated, failures and I too have found scenarios where blindly following the ECAM would have you go down a path that only make things worse. (Both outer fuel transfer valve failures is one I can think of...). I know you were not asking about ECAM, but my point is you can't leave your brain at the door just because you go flying an Airbus.
I have not tried an FS calculation with the failures you mention but my gut feeling says Vref+45 sounds reasonable. (As a side not, I just happen to remember on the 737 it was Vref+40 for landing with flaps/slats up.) Before I decide what speed to fly, I would check it with the VLS and see if they match up some what. The body attitude is also of concern, as is flare authority with only B system available.