Can I use my turbo tax desktop license to file returns for my non-dependent children? If so, do I use my intuit account or do I need to create one for each of them?

Using the TurboTax desktop CD/Download editions you can complete and file as many tax returns as you want using the software you installed on your computer.  You only sign onto your TurboTax account when installing the software with the license code.  After that there is no need to sign onto your account again.  Unless you will be installing the software again on another computer that you own.