In ceiling set up with Pis

Hi guys, I am planing to do some renovation at home (bathroom) and would like to have your opinion on the following set up with in-ceiling speakers
the current idea would be the following:

- in a closet
Player - Raspberry Pi 3 with Hifiberry AMP2
Wires to speakers


- in the bathroom
Another Pi3 with Touchscreen to control the Player (music and volume)

I have 2 questions:
- Is AMP2 safe - not getting too warm?
- Can it go on standby when not using the player?

or better to go with a small Amp with just a Pi player

Thx for your ideas/feedback.