they should have received form 1099-NEC. with that form you link to schedule C which carries to schedule 1. form 1040-SE is automatically generated which carries to schedule 2.
form 8615 may or may not be required. here are the tests
the form must be filed for any child who meets all of the following conditions.
1. The child had more than $2,200 of unearned income. (what you paid them is earned income)
2. The child is required to file a tax return.
3. The child either:
a. Was under age 18 at the end of 2020,
b. Was age 18 at the end of 2020 and didn’t have earned
income that was more than half of the child's support, or
c. Was a full-time student at least age 19 and under age 24 at
the end of 2020 and didn’t have earned income that was more than
half of the child's support.
4. At least one of the child's parents was alive at the end of
2020.
5. The child doesn’t file a joint return for 2020.
you may have a tax issue by not issuing them form w-2 (not a 1099) for their compensation. but that's a matter between you and the IRS.
