The epoxy; both thin-set and grout, would hold. the tile would probably chip, crack and break out. Epoxy tile does not like flex in the substrate at all. The epoxy would flex some; but it is hard enuff for the tile to compress against the grout and chip. Another look at it might be the silicone grouts offered?
I think the 'fair and paint' is the best/quickest option. Next would be the teak grating.... very nice touch on a boat. Another take is textured, white (roofing) rubber, laid like sheet vinyl (or a roof...huh!
Lotsa option out there