What is the best way to play music with DAC/wireless?

Hello, I (an old fool just getting out from cd) have basic questions for digital format.

I have Aiff format songs stored in Mac/iPad/iPhone.
I play them by using app called Flacbox.

My question is, what is the best way to play these song?

1) DAC - Amp
This is my basic idea, for example, iPad/Macbook connected to DAC via USB cable then to amp.

2) DAC - Amp
Using USB thumb drive to DAC unit then to amp. Honestly I don’t know what advantages this method have over method #1

3) Streamer - Amp
Using Airplay from iPad/Mac wirelessly with Streamer then connect a streamer to amp via cable.

I do not want to pay any kind of subscription service (though it has a free version). I want my system to be closed one without internet connection. (Only using router)

For method #1 and 2, I consider ARC CD6 and PrimaLuna Evo 100 Dac. No idea what would work better.

For method #3, I have no idea what models are equivalent to models I mention above. (Good DAC with Airplay support) Most of them focus on streaming service that I do not want. Also not sure which one can work out the best with Airplay. (Only wireless solution that I can use free. I feel like airplay is still better than bluetooth.)

Please share experience and advice how I can get the best sound quality. Also if you have any model recommendation, please share some wisdom, especially airplay supporting one. 

Again Please feel free to educate me. Thank you.
The only SQ worth your time is from a dedicated streamer wired to a DAC.
Or just get a BluSound 2i.
Put the files on a thumb drive or SSD in an Orico case and play them with the BluSound App.There are plenty of commercial free stations to find.
Forget Airplay. It will NEVER sound as good.
I don't stream yet, but for the playback from HD I chose Airplay.  WiFi makes all things on the computer side irrelevant.  You can use any computer with any speed and any amount of RAM and it won't make a difference since what is being send is data in packets with no timing involved.  Initially I had problem with dropouts, but it is OK since I switched to 5GHz band (more channels, less traffic).

The only thing that matters with WiFi is quality on the receiving end.  My Airport Express outputs optical signal with small amount of jitter (280ps).  According to what I've read jitter becomes audible above about 50ps.  280ps is not that bad, but fortunately I use DAC with strong jitter suppression.

From two other choices I would pick #2, because #1 can affect performance by injecting computer's electrical noise into DAC.
Other than injected noise async USB should be perfect being similar to WiFi (data transfer with no timing involved).
I just started using a Chromecast Audio into a DAC via my Iphone
used on Ebay 50 bucks. sounds very nice
I have been wirelessly streaming my lossless ripped CDs (AIFF or ALAC) using various versions of Airplay for about 11 years. I have 3 systems in 3 different rooms and my wife has her own system. Two systems use the most recent Airport Express and two use 3rd gen Apple TVs using the optical out into stand alone DACs or an integrated with an internal DAC in my wife's system. Our music files are stored on a Mac Mini running headless. We use our iPhones or iPads as remotes to control our music selections. The sound quality is excellent, actually better than any of the CD players that I have used. I have never had any issues and never had a dropout. It just works flawlessly.

I did audition several music streamers but either we could never tell any difference or they didn't sound as good as my current setup. The Bluesound Node 2 with its internal DAC did not sound as good as an Airport Express with any of my 3 stand alone DACs. When I used the Node 2 with my DACs, I cold not tell any difference between it and the Airport Express.
It sounds like your system is what I want to set up. I also build up music storage with AIFF and want to use iPad as the remote. Since apple does not support Airport express anymore, I think I would start with apple tv path. Can I ask what kind of standalone DAC do you use? I read couple reviews that Bluesound node 2 is not an ideal solution. I was thinking about Lumin or something, but still not sure what would be most efficient way.
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I love the Exasound Sigma Streamer/e38 DAC combination. I stream my own music on a NAS, high Res music from a music subscription site, DSD, FLAC, etc. 
But from an iPad, all you need is Airplay. And it handles AirPlay plus room for expansion.