Hi, I don't know whether the question here is correct, but:
1) Yes, that is possible. Basically, the Ultra allows you to mix signals together and plug two instruments at once. The separation for the output is done easily, either you can use the Out1 for one instrument and Out2 (FX loop) for the second. If you would like to use the XLR outputs on Out1, you can use Pan blocks in the chain and pan each instrument to each side. I have done this when jamming with a friend through the Ultra - two guitars, two inputs, one on left channel, one on right channel. You can search this on youtube on generally on the google, there are guides on how to do this (and, correct me if I am wrong, the setting is pretty much the same for Axe FX II, so you can get inspired on this setup from there as well).
2) Whether it is worth... that is hard to say. There are people (I can totally relate to that as well) who say that the Ultra is the best entry-level Fractal. It is not pricy (I bought mine - middle Europe - for approximately 800 euros/790 USD), the quality of the sound is still pretty good and, at least from my point of view, the sound feels more natural than from e.g. Helix (even the LT version). If you would be going for only the effects, then the question is what kind of effects are you going for. The magic of Fractal, in my point of view, lies in endless possibilities and very fast changing of presets while not having to dance around your pedalboard. And that what for me the point where I knew I wanna go for Fractal. Hopefully it will help you somehow, if not, feel free to ask more questions!
