I have been polishing my guitars every string change for the last 5 years. I always polish the fingerboards too. I spray the polish on and take a cloth and rub it and shine my frets and the wood. I have rosewood and ebony fingerboard too. It's never done any damage and it looks very nice. I know I should use actual fretboard conditioner or lemon oil but will polish hurt the actual fingerboard ?? I don't see why it would but I want to make sure.
It will not damage the fretboard, but the wax in the furniture polish might build up and get rather gummy after a while. Better to use a good fretboard cleaner on the bare rosewood and ebony fretboards.
I use guitar polish. I don't think there is wax in it? I just used lemon oil on my 25 year old Gibson Sg's rosewood fretboard. It really shined it and made the wood feel really nice.
Some guitar polishes have a wax base in them - that is what makes the surface of the guitar shine. But if it is just a lemon oil cleaner, then it should be OK. Do not overdo it on a rosewood fretboard. Rosewood is more porous than ebony or maple, and too much oil could conceivably cause the wood to warp. An occasional cleaning is just fine, though.