I think you are correct in that FLAC files do not have the sharing and compatibility limitations that Apple file formats do. However, if you're happy with iTunes and are willing to continue using Apple file protocols, then you could always rip your CDs to ALAC, which is (allegedly) just as good as FLAC in terms of the amount of information retained. That way, you can use your laptop to play back all of the files using Remote on your 'phone/tablet.
If you would prefer to continue with FLAC and foobar2000, I found this:
I have no experience of either foobar2000 or the remote app, so can't comment on how well it works. I can tell you that in my system (iMac + iTunes + 3 x AEx) , the Remote app works brilliantly. Apart from a slight delay on first use (when the compute wakes up from 'sleep'), it is really quick to use, offers all that you need to playback songs, playlists, albums, etc. It also enable you to search for tracks/albums, and to enable/disable different Airplay devices and control the volume of each separately. You can even use Remote to create and edit playlists. And, because it's free, it's the best value app I have...!
I also spotted this further down my previous Google search:
It would appear that it may be possible to control foobar with the Remote app. I've not tried it and I did note that the article is quite old, but you could experiment free of charge. Provided you can put your laptop near your amp, you should have a really capable and user-friendly set-up with the microStreamer. Job done!
Please do report back on what you found works well so that I can add it to my 'memory bank'...!
Brilliant stuff! Thanks very much for the great info!!
I will have a go when the HRT turns up. Still not really figured out how to use foobar2000 yet... Still in the process of ripping all my cd's.
Will give you an update in a few days hopefully.
Sorry for the big delay but I have just downloaded the app from google play for foobar and spotify for that matter and both work brilliantly! Couldn't be happier. Thanks for all the help!!