Typically no, account numbers will stay the same upon streaming to the platform. Signing the LPOA will allow XYIS and CLS to act as subadvisors on the account, but will not change the account number.
The only times an account number will change for an account is if it was at the retail side of TD and you move it to the institutional side of TD in order to manage it or if it was a Scottrade account that is moving to the institutional side of TD.