I'm happy to report that after a week suffering this issue, on a whim in System>Security>Authentication I noticed that on my working cams "RTSP Authentication" is set to Basic whereas on the new one its default is "digest" so I changed it to digest/basic and BOOM it worked instantly! I also noticed there is a new addition specifically for Web Authentication which I'm not sure if I should leave on digest or also change to digest/basic. I maintain that the illegal login lock is not an issue.
P.S. Don't you hate when people solve stuff and don't pay it forward!
*Correction, while it resolved the issue, changing settings over and over caused the illegal login lock problem to resurface so unless you want to get locked out for a half hour it's best to just leave it off!