Hello Scott.
I can understand where you are coming from. Computer audio is indeed overwhelming when you first approach it, and even the "simple" guides are tough to crack if one is not computer savvy.
Here's an attempt to try and help out with the simplest solution I can think of with what I would expect as good sound. You already know these are all balancing acts, so maybe what I think is the balance between complexity and sound that you expect is off mark and your feedback will help us adjust to your needs.
Start with a dedicated computer, meaning it will only be used for audio. Go with Mac or PC, whichever you are most comfortable with. You mentioned a MacBook, so I will assume you are more comfortable with Apple. A Mini would also be fine. We could go on and on about optimization, but I think not now.
Software: iTunes isn't good on it's own, but users report outstanding results using Audionirvana+ running on top of iTunes. With that you should be all set software-wise.
Getting the info out of the computer is a critical link. You mentioned your Hegel has built-in DAC. Is it an asynch USB DAC? If not I suggest you get: a) a USB to S/PDIF converter, or b) an asynch USB DAC.
I would probably get an Audiophilleo 2. I have one (mine has the PurePower option, a significant upgrade, but you don't necessarily need it at this stage). Of course there are other good units too. The point of this device is that by having asynch USB the computer clock is slaved to the Audiophilleo clock, of much higher precision, reducing jitter (hence improving sound). The Audiophilleo connects straight into the coax digital in in the Hegel DAC section, so you don't even need a digital cable.
Music storage is important too in the sense of how it will connect to the computer. If using USB to get the music out of your computer you don't want to use a USB hard drive to store the music. Hopefully your mac has firewire. USB means universal serial bus, and being serial means that data transfer in and out are in series, apparently increasing jitter. A USB hard drive will still work, mind you, just not sounding as good. I used this for a while when I was getting my toes wet in computer audio and was happy then.
And I think you are set to start. Generally the wifi built into the computer is electrically noisy, so turn it off when you don't need it.
Needless to say there are endless improvements you can look into later, but learning first if computer audio is something you like enough is a sensible way to move forward, in my opinion.
Enjoy the journey!