If you're a small business, you are likely to receive a very small number of such requests, if indeed you receive any at all. For most small businesses, someone would simply do a manual extract/delete of the data if it was ever requested.

Regarding backups, realistically you are not going to be required to delete from them as it's completely impractical to delete a single user's data from backup. You just need to be straight with your users - tell them that their data will be removed from your live system immediately, but that some data will remain in archive, securely encrypted, until the end of your defined retention period.