Hi and welcome to the community!
I'd like to introduce you to h-node. H-node is a hardware database which
categorizes different kind of hardware like laptops, desktops and their
internal parts based on their compatibility with free software.
H-node is a good place to find freedom compatible hardware. You should check
that out and also contribute your existing hardware to it.
Can you boot your mac with a Trisquel live-cd and report the results to
h-node? It would be nice.
Good luck with converting your mac!
