Hello _Rei_, and welcome to the forum.
1) Wondering if this is a false positive since this is coming from a site/company I've been doing business with for the last year or so. If it's *not* then I'll advise them right away (might do so after typing this anyways).
2) The EMail in question is still in my inbox but with ***VIRUS*** added to its title. Can I open this Email (in my mail program) now? Meaning, did Avast clean it up? I know AVast put at least a copy in the chest. Just wondering if the one left in the Email software is safe or not.
I would NOT open the email since Avast gave you the Virus alert for a reason. Instead I would permanently delete it and as you suggested contact the company that sent it. Perhaps they can fax you a copy of what was sent to you and investigate the reason. Perhaps their site was hacked or there was a malicious script or many other reasons that caused this alert.
If something is sitting in your Virus Chest, it is safe there because it is quarantined. However it is not safe in your email software since Avast didn't clean up the email...it just put it in a safe area (Chest), so that is why I suggest you delete it from the email location
without opening it.
Have you updated your Avast definitions and run a scan since getting this email? Which machine was this on?