Wifi card
So my current laptop does not have a supported wifi adaptor under Trisquel. I am willing to try and buy a new one (I will go shopping tomorrow and see what I am able to find), but I also need to know what brands I should be looking for. It seems based on a bit of reading, that Atheros chipsets would be a wise choice, but just need confirmation.
Wifi cards with a chipset driven by ath9k are indeed usable with free software only (however, if it includes Bluetooth as well, this part may not work). The problem is: it is extremely hard to know what is the chipset of a Wifi card. Along time, a same model can go from a chipset to another.
The only vendor I am aware of that guarantees that the devices it sells run with Linux-libre (hence with a 100% free GNU/Linux distribution like Trisquel) is ThinkPenguin. By using this link, 25% of the benefits on your purchase will be donated to the Trisquel project.
Another solution is to search for second-hand cards whose vendor indicates the chipset.
In a related note, does swapping out the card result in a new MAC address for the wireless Internet connection?
According to Wikipedia, the answer is no:
MAC addresses are most often assigned by the manufacturer of a network interface controller (NIC) and are stored in its hardware, such as the card's read-only memory or some other firmware mechanism.