[RedBaron]

Do you use the adaptive cruise control? I've heard it's very hard on brakes.

Not sure where (or how you could) hear this. It only applies the brakes if you have to slow down urgently, in which case you'd be applying the brakes yourself if driving without cruise. I'd classify this myth as 'busted'.

 

[RedBaron]

The corolla, I no longer have, used engine braking when going down hills, why not the mazda?

The Mazda DOES use engine braking on mild downslopes, but it uses brakes if the speed increases above a certain amount above the set speed - on steeper inclines.

 

[RedBaron]

On the lads '16 CX5, there was a way to put the rear brakes into maintenance mode, which drew the EPB mechanism all the way back - for pad checking / replacement etc.
Is there something similar on the CX50?

YES! You WILL damage your rear brake calipers if you don't put them in maintenance mode when changing pads. Very expensive mistake if you don't.

Or is the temporary handbrake release method (s) enough - page 4-70 owners manual?

NO! That is NOT sufficient.