A Fibo panel becomes quite dense and traps moisture in the wall. In that case, I would rather put regular tiles directly on the wall without any waterproof membrane behind, so there's some possibility for the wall to breathe through the grout. If there's such a high moisture load, it might still be too dense if you tile a large area, which could result in the tiles falling off after a while. The safest option might be to sand down the existing paint. Repaint the wall with open silicate paint and then just apply one or a couple of rows of tiles above the countertop as a splash guard.
(The best, of course, is to also do something about the drainage)