So far as I can tell, RNC-Staufenberg should still be on the same account. It doesn't appear to have been tampered with. The other ship, Memphis, was renamed to ONE|NIGHT|IN|IBIZIA and also still exists on that same account. The only IP having showed up on the access logs for the ships is the same one associated with your forum account here.
Are you loading up the right account in your FLAM?
It is possible to get an already given account code. I've gotten 2 myself when making new accounts and had them have ships on them already. never bigger than a VHF but its happened.
As to movechar codes. what is that supposed to do? If someone got the acount and logged in they could simply set new ones and move it. (Tho this doesn't seem to be the case) setting them doesn't lock them or anything ya know.
Edit: Also, could you have accidentally deleted or renamed the account you thought they were on? I had to recover my accounts one time, and had renamed them since the backup was done. it took me a couple hours to get them all back to rights again. Just a thought.