I'm glad to hear you got it figured out. Your original post led me to think that you wanted to install Leopard but your Mini would only read the Snow Leopard install media, which didn't make much sense. As far as setting it up as a file server for your music, that's easy to do by just turning on afp services in the File Sharing section of the Sharing Preference Pane and adding your music folder to the shared folders list. It won't do things like AirPlay, but you don't really need that.
As far as converting your FLAC library to lossless m4a files, I think Switch will do that. Not sure. It would be nice if you post back what you find here. It's good to have a repository of information for those of use who are not so excited about the direction Apple is going with it's OS. It breaks my heart. I loved OS X. macOS is not so useful and literally hurts my eyes with it's gauche colors, hideously ugly gradients, jarring animations, and relatively cryptic and amateurish GUI. Change just for the sake of change is never a good thing. Snow Leopard was the last OS they actually got working well before they released another pile of problems. They need to slow down and do things in the insanely great way that Steve Jobs demanded again.
HEllo,
yes, at first I thought I would install Leopard since the SL disk didn't get recognised by the optical drive but it luckily worked out
Now I have to put screws back on the frame and slide the lid back in place and then figure how to use it without a keyboard which is no big deal but the thing which will bother is the need to switch on the TV anytime I want to use it given I will be using a DVI to HDMI cable so that the Mini can sit next to the TV and stereo system.
As far as conversion I am using XLD which is very easy and complete, no issues till now but a lot of music buried into folders which I either will never listen to or not like so also time for autumn cleaning.
With regards to Apple, well, my first Mac was a Titanium 667, the it came a wonderful PowerMac Dual G4 and on and on and on but quality of the hardware now is comparable to consumer PC products and the urge to update the OS each and every year only lead to a lot of whistles and bells to attract more people so, at the end, Apple became another commercial brand with very nice design but poor innovation, their target is annual sales of iPhones and accessories so it's no surprise the Pro share is quite disappointed and looking at other beaches.
Fully understandable that a company has to make money but I guess many of those who were proud Apple users back in time feel betrayed and small bits like not being able to sync my books onto my iPad are convincing me that the extra I have to pay for a nice design is not worth, bye bye iPad, time to evaluate a Kindle just to read...