Work with Logic, my mac Pro(2008) is old. Which one do I now need?

I need a new Studio for the Music School.

I have 2 Monitors,

Microphone Amplifier Focusrite Octopre

Analog Digital converter RME ADI-2

Sound Karte HDSP

Can I use them again ?

Which Mac is now in MINI with the full Power build up.

Or a Pro Mac again ?

Wich external Pieces do I need to work the same with 8 Microphones ?