https://codein.withgoogle.com/dashboard/org-students/?sp-page_size=1000 only lists "student display names" which can differ from user names across places.
Also, we need to make a cut compared to e.g. GSoC or Outreachy where the number of students is low and involvement way higher. Plus not all GCI tasks are code tasks, and quite some tasks were on GitHub etc. so it's fine and expected that some students won't be listed.

I took the list of student names sorted by biggest number of GCI tasks solved and tried to find them in our Bitergia DB.
I managed for our Top 10 in Google-Code-in-2017:
author_name:"Albert221" OR author_name:"Phantom42" OR author_name:"Rafid Aslam" OR author_name:"Divadsn" OR author_name:"Eflyjason" OR author_name:"Clockery" OR author_name:"Ryan10145" OR author_name:"Pppery" OR author_name:"Gabe Mitnick" OR author_name:"Priyanshu Ahuja"
and that becomes:

• https://wikimedia.biterg.io/goto/b0c288bba1e23712c9ac8c1fed3b53fd
• https://wikimedia.biterg.io/goto/6f02cd1f2475bf12c2f1ce41ca61e752

Note that currently these two queries suffer from T184741 (list includes 8 people, widget states those are 9 people).

For spots 11-20 I did not find entries in our internal DB hence I stopped.