Make it an option instead of a guarantee. There might be employees who would not prefer using crypto over fiat, after all, that is their paycheck, they probably use more than 50% for stuff that they need to pay. As for asking for a method, well, it shouldn't be that hard, if they wanted crypto in the first place they should already have their own wallets. If they don't I reckon you can prepare some paper wallets, no need to complicate it as much. It is going to be a temporary storage after all, until they can create their own which shouldn't take long imo