family, organic groups starting help needed?

Hi all,
I'm about to start my 1st drupal site and would appreciate some basic 1st step approach help.

I would like a parent to be able to create an account, enter in some details for their children, and have each child given their own page containing info (how they are doing, school reports etc) submitted/updated on a regular basis by the parent.
I'd also like a 'summary page' where all the children in the family are displayed on one page.
Other adult family members (who are site members) should be given permission to view the summary and individual child pages.
I think a 2stage password system is required,
1 for general readonly viewing, the other for editing their own child details
I'm assuming organic groups is the way,after lots of reading. But I need some help in defining, what i want in terms of content types, nodes, profiles, stories, pages, groups, permissions, editable fields etc.

Workflow would be something like.
Kid comes homes from school, browses to this family site, and without logging in! (remember me?), sees their current 'summary page', can click on their own name to see a detailed page and can see a summary of how their cousins are doing, when their birthday is etc. from a separate friends sidebar which they could click to see a detailed cousins page.

Then dad comes home and the child tells him that he got an A in class, so dad then clicks an edit button on the childs page, enters a password, and can then update the childs school info field.
Dad then logs out of 2nd stage permissions and the site reverts to 1st stage readonly state. But now cousins can see updated status in their own friends sidebar etc.

any guidance really appreciated.

Regards
Duncan