you must relaunch completely and destroy the old coins, or there will be a huge dump
It's not too mined. A dump will Always occur no matter what when you hit an exchange.
I think implementing KGW and forking it might the best thing to do when doing a relaunch.
Maybe Original creator want to give the coin to us?
Check with that guy.... what do you think about the structure? will you change that, or keep it?