My teenagers have T4, T4A, Dues receipt and RRSP contributions. Do I need to pay for a separate Turbo tax program for them as well as list them on my current program?

In TurboTax Online you pay per return. So when you make returns for your children, if you used a paid version of the software, you will be charged. If you use TurboTax Free, you will still see a payment screen, but the price will be $0.00 and you will not be asked for payment information.