Sorry, yes they each need to file a tax return for self employment income and pay self employment tax on it. You can still claim them as dependents on your return. You do not report their income on your return.
To file a separate return for a dependent you need to set up a new account. Online is only good for one return per account. You can use the same email address for 5 accounts. You can probably use the Free Edition or the Free File website
Https://ttlc.intuit.com/questions/1894512-how-do-i-start-another-return-in-turbotax-online
Be sure on their return you check the box that says they can be claimed on someone else’s return.
