Ok:

Part 1: I migrate metaperl.com to my linode and web service is cool. I then install postfix and get going with setting up mailman. I get some errors with some forwarding where it mentions mail.metaperl.com and I know I never personally setup a mail.metaperl.com so...

Part 2: I delete mail.metaperl.com from the MX records and from the subdomains. Now everything works but it was not due to the mail.metaperl.com thing. It was due to my misunderstanding of postfix regular expressions.

Part 3: the deletions mentioned in part II remain and I am happy with how things are working. But is something going to happen in 24-72 hours to start causing problems?

I symlinked my entire postfix setup from /etc/postfix to here -
http://www.metaperl.com/postfix/

if you want to look at it.

If it helps, DNSStuff reports you don't have MX for "metaperl.com". If you want to receive at "something@metaperl.com", you have a big problem. If you don't want to receive mail for @metaperl.com, it seems OK.