What I am asking is should the code be an L (dependent who lived with client), N (dependent who did not live with the taxpayer), O (other dependent) or Q (not a dependent, but is a qualifying person for EIC, and/or child & dependent expenses)?
We cannot answer we don't know your client but you should. So ask yourself or if you don't know ask your client ----- Is this a child that qualifies as a dependent: Did the dependent live with taxpayer? etc etc
If you still are not sure how to answer try reading this https://www.irs.gov/forms-pubs/about-publication-504