The clamps look like substitutes for cast iron leaded couplings. You should be able to remove any two above tub connection. Even if you break them,new ones are available anywhere plumbing is sold.
It would seem the line is gooked up inside which is best cleaned with a rotorory cable with scraper blades. If the floor drain cover will come off,a pressure bladder is simple and might do the trick. The bladder could also be inserted in tub if floor drain is temporarly plugged and someone watches kitchen sink for backing up. I would stay away from chemical cleaners.

can you take another pic of the pipe from the side? i want to see the wash sink connection