Unable to join 3rd server to domain. It already exists. Unable to use numerous means to cleanup FSMO to be ready for DCPROMO join.

I was in the process of converting all 3 domain controllers from 2012 to 2102 R2. All servers are VM. All servers were imaged first. Likewise I have console access if necessary. I had 2 servers built and sized with temporary addresses. I have them both fully patched and ready at the workgroup level. I had only two servers,but had to go to 3. (Long story). I had a server #3 built under 2012 R2, patched and protected. Took it to domain member and subsequent domain controller. I moved the FSMO from #1 to the new #3 as well as copying the database and exporting the CA functions. FInally I updated the GP to relocate the NTP from #1 to #3. I had some problems with SYSVOL and NETLOGON, but managed to copy and configure share permissions and all three domain are replicating. I Meanwhile I use the GUI to demote the #2 (2012 legacy) domain to member server which went cleanly. No forcing necessary.  YEY Bumped it down to workgroup and shut it down.  Brought the #2 new server to domain member and subsequent domain controller and again some SYSVOL and NETLOGON issues. Fixed the same way. So now I have two  2012 R2 domain controllers and one 2012 DC.  I changed #1 to DC from GC. dcidag, nltest, netdom, diags all look good. Attempted to demote #1. Did not work. Required forcing. I Went to #3 and attempted to use AD Sites and Services and it would not delete. (Yes. I unchecked the object deletion). I tried ntdsutil, adsiedit, ldp, some super duper script I got from technet. Nothing worked. I went to the two working systems and methodically searchd for and deleted all reference to this evil domain controller. I looked in the registry and deleted all #1 DC  references. Went back to AD Sites and Service and was able to delete #1. I took it down to workgroup and shut it down. I went back and double checked both working 2012 R2 DC and verified the were clean. I finished preparing the final 2012 R2 new server changed it to the IP address and hostname of the original #1 and brought it up to member server. I then tried to take it to Domain controller using the FSMO and I go the infamous "Domain already exists"  Been stuck there ever since. Naturally I have looked all over for #1 references again.  #2 and #3 DC are working fine and also running as GC. I have spent a long time online looking for ideas. Help.