I have 4 kids (8, 4, 4, 2yo) who each received a K-1 Form 1065 with ordinary income of $2280 ea. Can I file them in my return or individually, they have no W2s.

You are not able to claim your children's ordinary income on your tax return.  Your dependents are required to file a tax return if their unearned income is more than $1,050, or their earned income is more than $12,000. 

To ensure that they are required to file, click this Internal Revenue Service link: https://www.irs.gov/uac/do-i-need-to-file-a-tax-return and begin navigating through the screens.  

[Edited 04.06.19 | 9:34 PM]

Please refer to the edited version dated April 6, 2019 at 9:34 PM.  I have included the filing requirement for a dependent's unearned income.