ABS sensor

Evening,

Are the ABS sensor, tyre pressure monitor and mpg sensors all together or am i barking up the wrong tree?

the reason i ask is fuel economy according to MDI has been a bit erratic of late, i had a puncture the other day on NSF but no monitor activation (and it was completely flat beyond repair), when the car wheel spins brakes go spongey for a little while and peddle travel increases, also theres a droning noise at around 70 mph (can only hear it in the car), this appears to come from the front end which i think may be a bearing,  I have replaced the tyres and its still there so not them and it continues if the clutch is dipped, i have had it scanned and it shows no errors?  could this all be connected or am i way off the mark, i'm thinking wheel bearing and abs ring might need replacing, does anyone have the part numbers to hand.

the car is fl tdi estate

thanks