Mac Mini or MacBook to Tact to MF X-DACv3

I am thinking about buying a Mac Mini or MacBook with digital out to use in my audio system to augment my current CD playback system. The plan would be to rip to Apple Lossless some CDs I listen to frequently and to have them readily available to my system.

Some questions from someone who's only moderately technically literate.

First, I use an old Tact RCS 2.0 in my system. It accepts digital signals up to 96/24. Then I send the corrected signal digitally to my Musical Fidelity X-DACv3, and then output the analog output from the DAC to my Arcam AVR300's analog in, and then I play back using the Arcam's pure analog mode. If I use either Mac product in the way I'm thinking, sending the Apple Lossless signal out digitally to the digital in of the Tact, and then out as described above, is the signal coming out of the Mac product automatically something that the Tact can, for lack of a better word, understand? Same question if at some point I take the Tact out of the chain, sending the Mac's digital stream to the outboard DAC directly. Don't the Tact and the outboard DAC only "understand" signals looking like 44/16, 44/24, or 96/24? How do they understand and then manipulate a digital stream like that which comes from Apple Lossless, or a regular AAC file, or an .mp3 file? I'm probably not understanding something really basic here, and I apologize if that's the case. But I want to be sure that my current equipment will be able to take the digital out from the new Mac, whatever file type it is, and be able to manipulate it, either to apply correction to it in the case of the Tact, or to be able to convert it to an analog signal, in the case of the external DAC I own.

Second, I read a question out on a forum that suggested that the digital out of the Mac Mini is volume controlled. The person posting the question was wondering whether this could be defeated, saying that the volume control would degrade the digital signal and make the digital stream inaccurate relative to the file. A. Is it true that the Mac Mini has a volume control for the digital out? B. Same for the MacBook? C. If so, was the poster right to worry about the degradation of the digital signal being sent out of the computer?

Third, is the digital out on Mac products basically good? I've read posts from people saying that the USB out is better. If it's much better, such that you'd recommend I go that route, would you also recommend that I look for a different DAC? Or is there some sort of USB to coax digital or optical digital converter, so that I could get whatever benefit to there is to USB out, while still keeping the DAC (and Tact) I have now. Maybe I'm not even posing the right questions with regard to the USB option, so please illuminate me if I'm not.

Thank you very much for your help.