If you are close enough to the Emotiva to plug the laptop in to USB, you can control iTunes with the Remote app on your iPhone/iPad.
If you want to stream from your computer that is in a separate room, you can also use the Airport Express (or a cheap knock off with Airplay) to plug into the Emotiva. The Airport Express will show up in iTunes and in the Remote app in iOS.
I haven't tried to play FLAC files in iTunes in a while, but if it isn't possible, there are several different programs that will convert the FLAC file to ALAC. (DbPoweramp, XLD, to name two).
I received my CCA and accessory mini plug to Toslink cable over the weekend. Set it up Sunday, running the Toslink into my Emotiva DAC. I uploaded my iTunes into Google Music Play with the Music Manager, installed the Google Music Play app on my iPhone and iPad and began listening. I am astonished by the beautiful sound quality. To my 70 year old ears it sounded as good as a CD (I guess some would say that is not so good). On Monday I bought a second CCA/Toslink setup for my other house. Will set up this weekend.
Thanks to all for their patience and helpful input. I have, however, a few naïve questions.
1. If I am not "casting", but simply play music on my iPhone, am I using data from my data plan? . It is my intent not to use my data plan.
2. Is there really no charge for the upload and use? Am I using a Google 'Cloud" for free?
3. Is there a Music Manager app, or do I always have to download it from the website?
4. If I rip more CDs, do I rip them with iTunes, then ask the Music Manager to upload again?
5. I have ripped in FLAC using Media Monster. Do I have to convert these files to ALAC in iTunes in order to upload?
6. How do I know how much of my allotted capacity I have uploaded?
Answers to some or all of these questions would be appreciated.