Different motors, will not work. Likely you have a 5SFE in the celica? The rolla is a 4AFE/ 4AF.
eage1 had a weber 32/36, I think it was. Had one for sale, not sure if he had sold it yet. But you have that option or do a motor swap for a 4AGE 20V or 4AGZE.
In my sedan, I did find that there were rear speaker wires running back there (FACTORY!) but the car never had rear speakers. So likely, the wires may be back there where factory speakers would go. I think right behind the C-pillar would the location... If not, you could always run the speaker wires yourself
As for the climate controls, they're all wire cables. I think you may be able to adjust them. You'll have to remove the dash portion and there should be 4 or 5 screws to remove the climate control to see the cables. Not too sure, haven't messed with anything for it yet but I've noticed it from times I took the dash face off.