Okay, you really have one of two choices:
1. You can get together and tell your employees that you want to start their first date of employment as of Oct 14, 2013, and that for their work done prior to that date, you will turnover all of the money set aside for their payroll taxes to them, and give them a 1099-MIsc at year end for the gross amount of money, and they will have to report their taxes as self employed, Schedule C employees, for that period of time.
Then, you'll have to cross your fingers and hope that neither EDD nor Uncle Sam comes looking, and that none of the employees decide to file a claim that you were misclassifying them as independent contractors during that time period. Definitely risky, but if you succeed, then you won't have any penalties.
2. You can contact EDD and the IRS and explain your error, and then let both agencies impose whatever penalities are required by law. You may get stuck with an additional payment plan to pay off the penalty amounts -- but, there is nothing in the law here that protects you for making an honest mistake. Penalties will be imposed for failure to procure workers comp insurance (if you did not), unemployment insurance contributions, State Disability Insurance payments, and failure to remit FICA (Social Security), FUTA, and Medicare payments to the U.S. Treasury.
I can't calculate the penalties. You would need a CPA to handle that task. Though, it really doesn't matter, because if you decide to choose option #2, the penalties will be what they are, and you'll just have to swallow them.
There actually is a "door number three," now that I think about it. You could close the business right now, and tell your employees, that you will give them all of the money set aside if they agree not to report you to the government -- and that this was all just a giant mistake on your part. You'll be risking that someone files for unemployment compensation -- if they do, you're SOL.
The point here is that unless you choose option #2, you are at the mercy of the employees and their respective understanding of tax law, and the penalties you will suffer if they decide to make you the enemy. Whereas, if they were each to simply take the money, pay their taxes and move on to new employment, you could potentially escape unscathed.
Please let me know if my answer is helpful or if I can provide further clarification or assistance.