I highly doubt they disclosed classified information.
The LOR will ruin their careers. As for their clearances, unless they claim something to the effect of “yeah, I knew I was disclosing confidential mission information in exchange for payments” they will probably retain their clearances. However, taking money is the worst aspect of it. Their re-investigations will take a while, that’s for sure. They’ll probably be transferred to guarding barges first. I.e., a transfer to a job which doesn’t require a clearance so there is no authorization for a renewal, ergo no clearance.
On a philosophical note, as the late Mad Dog used to say, “ A letter of reprimand is better than no mail at all.”