MFS, you get max $500 for the Freshman, $2k for the 16YO, but nothing for either if you're not the Custodial parent (they lived with you >1/2 year).
No education benefits for MFS filers; No benefits for non-custodial parents ...
Education benefits: https://www.irs.gov/publications/p970
Dependent Rules: https://www.irs.gov/publications/p501
