I suspect you could split wood that way with the fillet knife. The Mora is a better option because it is a thicker blade, but I think the Rapala would hold up to that. I guess I'll have to give it a try and see

As far as cutting down the blade on your other knife, a Dremal tool isn't a bad option. A bench grinder with a fine wheel is good, and so is a belt sander. I have a lot of experience shaping steel, although none making knives, but I'd grind the bottom to shape it, saving as much of the factory hollow grind as possible, then work on the edge.