Streaming from Mac library using iPhone for remote?

Hi!

My husband has a huge music collection on his PC laptop and a stereo receiver with speakers all over the house. Right now he streams from laptop to stereo using an AppleTV connected to the receiver, but it’s pretty cumbersome to have the laptop up and operating out on the deck or wherever and obviously not conveient to carry around!

We are considering getting a Mac with a large harddrive to hold his entire music collection and to also hold all our movies from iTunes. So everything would be housed on the one Mac.

We currently have an AppleTv and are considering getting an Airport Express. We have multiple iPhones and iPads.

So my question is this: If we connect the Airport Express to the stereo receiver will we be able to stream the content front the Mac (NOT THE CLOUD) using an iPhone or iPad to view the contents and act as a remote? How would that work? Obviously the Mac would need to be on, but would it need to be “awake” prior to starting to stream?

Would we be able to stream from that same Mac to the AppleTv, again, not using the cloud - as in cases when the cable might be out) using the AppleTv remote?

Any additional apps or hardware we would need?

Thanks so much!