Mastering with AXR4 - set up and monitoring questions

Hi, I am asking if it is possible to use the AXR4 for mastering purposes?
I would like to insert external hardware via the analog outputs and insert everything via the analog inputs. Everything should go out from my master track and return to it.

What about the levels of my speakers and headphones? And what is the best scenario for that purpose?

I know from experience with the Lynx HILO that it works fantastic as each channel has separate chips and I can adjust levels easily.

Does anyone have experience with such a situation. Can I monitor everything in regards to that situation?

Thanks in advance,