What should be the correct pipe routing in case someone has put them back wrong.
I was merely mentioning the gearbox breather in case you thought it should be attached to something, but it is intentionally floating loose. The two small plenum hoses (rubber, not plastic) are post throttle breather and carbon canister pipe* (*from one of the four pipes at the back of the plenum to the breather box at the back of the engine) but these are not heater related anyway so can't see them getting muddled up.
Just out of curiosity, if you switch your engine off after a run and pull a vac pipe off (one of the plastic pipes with a rubber end piece), do you hear a hiss. You should hear a slight hiss from the air being released from the vac reservoirs. Vac pipe routing is in the maintenance guide if you need to trace where they go to.