oh Oh!! Furnace foil ducts torn-help!

[WillowRun]

oh Yeah. It is chilly willy here in NC tonight!!!!
Speaking of which.... fired up our furnace and realized that there was way too much heat under the sink. Low and behold the duct work under the sink and behind the kitchen drawer has rips in it.
No big deal to fix BUT two of the ducts are foil but one is like a gray membrane plastic type hose but soft. Why ?what is it ?can we make all three connections foil or is there a reason this grayish one is heavier and does point to floor vent of Rv??
Seems the 'black sink pouch (guess to make plumbing more accessible ?) got three duct hoses pushed too far....not sure how to roll up that canvas bag thing either- any tricks so it leaves the duct work alone but does bot hang out from under the big slide!?? LOl

Thanks in advance gurus!