Lookup from multiple names in one cell

Hello,
I need some help setting up a sheet that is checking what parents are engaged in our portal.
I have a "download" sheet that comes from the portal provider, that is in the same format. *attached copy*
Each student can have 2 contacts and they each have their own row. However, if the parent has multiple children, they are all added into the same cell on this row.
We would like to be able to have our list of on roll students on a student tab. Then to download the portal information, update the download tab and then have the details on the student tab updated.
We would like to see each child and when their contact 1 and contact 2 last logged in. However, their name could be the first child, the fourth child or the eigth child listed in that parent cell.
Parents can also differ between children. (4 for one mum but only 2 for one dad)

Some help trying to set this up would be much appreicated, don't know where to start as the values are altogether.

thank you

This looks great, thank you.
I'm going to try it with the real downloads!
:-D

So it doesn't seem to work with the actual data for the numbers.
The download page goes to around 3,000 rows, would i need to edit the formula to accomodate this?