It all depends on the amount of movements you need. I have test shots with the 43XL, and it will work unshifted. If you're picky about color and don't want it disturbed by crosstalk you can't move it off center almost anything, but as we've seen from Guy's Credo 50 testing you can stretch it quite a bit and still get results that look good.
With the same type of stretching the limits it seems like the 43XL would do about 10mm shift on the long side (similar on the short side), which can be enough for a 44x33mm back. If you're into stitching you'd need more, or if you're like me both interested in being able to use most of the image circle and don't like to push a sensor into crosstalk it would not look like a good combination.
I have haven't run Phocus much and don't know it's LCC capabilities. The CFV-50c doesn't present (strong) tiling or ripple fortunately so you won't need specific algorithms to clean up movement artifacts (like some of the Dalsa sensors require), so any basic LCC algorithm should produce a good result. When it comes to crosstalk you need a demosaicer that is robust against green channel separation (one green will get leaks from red and the other from blue so they will separate in the case they should be the same, which can cause the demosaicer to produce false detail and mazing artifacts). The demosaicer in Capture One is robust against this, but that is not the case in all raw converters. I don't know what it is in Phocus. My guess is that it will work, but I would like to see it in person first.
And no I don't think it's great marketing to put out these combinations without a disclaimer, but let's hope they inform the potential buyers before buy of what the limits are and not only go on about the advantages of live view and high ISO. From a lens with a 110mm image circle you get ~75mm usable when stretching it, and that may not be what the typical user is expecting to get. It will be perfectly fine for some though, 75mm is more than the Digaron-S 70mm.
But it's also about the upgradability of the system. You need to inform the buyer that when you want wider angle than this starting 43mm lens (which is not super-wide on a 44x33mm sensor) there are limitations, the SK35 and SK28 will be even more limited, so limited that you probably want the Rodenstock Digaron series and that may not seem like a good option for a system that is market as a low cost MF system.
If you have all the facts on the table, it can still be a good option in the end for your shooting style and budget, and I hope to see the live view backs on tech cams soon.