On a converted rosewood fingerboard fretless bass I've got (an old aria pro II), the rosewood hasn't chipped. It's so soft a wood that I doubt it's likely to chip, but when I used roundwounds on it, and slapped a lot, they'd grind a groove into the rosewood the entire length of the string, and getting deeper higher up the neck.
As stated earlier the solution is to plane the fingerboard and start anew. Eventually you run out of fingerboard and need to epoxy it if you use the bass enough. My solution is to use flats instead of rounds, though I do like the sound of rounds on a fretless.
Slapping on a wish is a bit wonky due to the extra long scale length--the fingerboard gets in the way. If you wanted to have a wish suitable for slapping, I'd suggest having him put a shorter fingerboard of 24 frets or less on a custom order. I'd also have him route the pickup further away from the bridge than he usually does (personal preference), and have him drill a ground wire tunnel between the electronics cavity the trem bridge too (wish isn't concerned about grounding).
As for putting a trem/vibrato bridge on a wish, shouldn't be any different than putting one on any other bass. Wish's bodies are thick enough to accomodate it.
