A polar orbit would be radiationally different than an equitorial orbit. Also, think of the Europa like effect of induced currents in your water layer. Enough to produce heat I think. Also, it would probably be strong enough to effect the orbital dynamics of the planet over the long term. Thinking about the direction of the induced currents (and making a few assumptions), the magnetic field would push the planet slowly out of the magnetosphere of the pulsar. Or at least give it a slightly slower orbit at the same radius.

Theres alot to consider with a planet this close to an exotic astrophysical object. I'll work on a list...

Also one should consider other phases of water like those assumed in the Earth's mantle and what they're solvents with. It probably safe to assume that these planets would be VERY metal rich.

Neat idea...