You should take a snapshot of the current Bitcoin blockchain and use that as starting balances rather than having people send you old private keys.

Also make sure to have replay protection in BitcoinCashClassic like BCH did so there is no unexpected problems with sending XBS.

You will have a lot more support this way than having people send you old private keys in a google form/email/PM etc.

This post is not an endorsement, just my suggestions.