2. The email came from firstname.lastname@example.org so pretty sure it is legit. I am more than happy to remove anything that breaks any kind of copyright but it would help to know what that might be in the first instance.
Check the email header and find what SMTP server it came from. Phony emails will come from dubious named hosts, often gmail or yahoo servers. I find it odd that MS legal would be contacting you about an IP infringment - Why hasn't the plaintiff conntacted you directly?