Linux preinstalled is going to remove a lot of candidates. If you relax your requirements to include known setups/components that work well with Linux then that would help expand your options. The amount that Microsoft gets from the preinstalled license is likely negligible.
A) You can chose what you’re seeding.
B) Just because you’re seeding something doesn’t mean you’re executing it. So, at worst, you’re transmitting a Trojan.
Someone can correct me if I’m wrong on some attack vector via seeding I’m not aware of.
Been doing it for a while - WvW and Open World it’s been great. I wouldn’t try and do raid rotations on it.