For the gut hook, I'd use either a round rod-type sharpener (ceramic or diamond), or something very simple like a dowel with some wet/dry sandpaper wrapped around it. In fact, the sandpaper would be my first choice; it's cheap and very versatile, with many grit options to choose from. Ditto for the convexed blades; they could be touched up on some sandpaper laid across a flat and somewhat forgiving surface, like a book or magazine/newspaper. Just 'strop' the knives on the sandpaper. Same exact technique could be utilized on a harder surface, like a flat wooden board. On the harder surface, the sandpaper will work more aggressively and more quickly put some 'bite' back into an edge. Maybe take some masking/painters tape to secure the sandpaper to the board. I was using this technique on some of my knives yesterday (carbon steel, 420HC and D2; all convexed edges), and it works great.
You CAN use a rod-type sharpener for all of these, if you want. It'll do fine to put a good working edge on any blade, especially if a diamond rod is used. Ceramic rods will be slower to restore a very worn or damaged edge.
