When you have one U-Joint & one CV the rotational speed change occurs either side of the U-joint and increases with the angle of that joint. Since the CV is just that it will transfer the rotational speed difference either thru the tire or into the transaxle gears depending where the U-joint is located . If its thru the tire the sidewall will try to absorb it, low profiles will make it worse. If its thru the trans then donuts or some form of elastomer etc will help. So the CV wont help with reducing the effect of phaseing other than placing the CV at the greatest point of half shaft angle change which will depend on some other factors like trans height in relation to axle hub.
I think the CV (constant velocity) aspect of a CV joint makes it unnecessary.
Mixing a CV and a U joint on a half shaft sounds like a certain receipt for disaster at high speeds. With 2 U joints, equal angles and proper phasing, you can almost eliminate the inconsistent rotational velocities between the wheel and transaxle, and the shaft's vibration is isolated to the shaft, but with one CV and one U, your transaxle in the middle is getting a beating.