Hi,

For the supply, if the two PICS have a COMMON GROUND and BOTH a very close to 5 v supply ( do not forget PIC protection diodes on the inputs ...), I don't see any problem ... as your sensor impedance is low enough.

For common Ground ... keep in mind there should be only 1 common ground connection point to avoid "ground loops" ...

Alain

a scheme of each of your ADCs inputs could help greatly too ...