Theres two things from his initial reply email that scream scammer.
1. talking about ebay third party protection. I'm pretty sure they dont have that, this isnt an ebay transaction, so why would they give a fuck.
2. if someone has to tell you that this is 100% not a scam, its a scam.
not to mention the wording of the email doesnt seem like that of a real person, or atleast one that speaks english on a normal basis, while it is a lot better than most scammers, theres still something just "off" about it.