ChristianJ.. The artificial feel built in to the Boeing flight control needs speed input and from memory it used a different set of pitot tubes for that. It did not use the regular pitot information provided to the flight instruments. Those tubes were also heated, but my suggestion is that if the flight instrument tubes iced up, then the feel system pitot might also be iced up, thus causing the feel to be incorrect. Hence the feel might be wildly inaccurate under those conditions.
I am not aware of any way to turn this system off, but in the old 737 you could turn off the hydraulic system that powered the feel and it was a strange experience to fly an airplane without any feedback. As some have said, like a video game. I never did hear of any problems with the feel system on the Boeing, but it might have had some effect on the two 757 accidents. Since the 'Bus does not have the system it would not matter.
The Boeing checklist has a table of thrust and attitude for various configurations and speeds, to cover this type of emergency. Does the 'Bus have that, and is it accessible in flight? (paper or plastic)
Would the crew have been trained on this?