I do understand your request, because obviously parents would want to be involved, even with older kids. I believe strongly in parent involvement, but you need some sort of trade off between parent's wish to see/control/understand what their kids are doing, for a number of reasons. At the same, obviously, kids do not really want their parents to look over their shoulder, for even more reasons. For younger kids, the parent could simply share their password and look .-) For older kids, maybe parents could be allowed to see everything, expect what kids put in their 'private' folder. It makes sense to separate in some way. To let inquisitive mothers loose everywhere will not be popular with most teenage kids I know.
Anyway, I think it would take a lot of clever coding to create such a 'ghost' user, and the security aspect here is another thing. Not simple, from where I sit.
Let us know how you fare :-)
sounds similar to the concept a client approcached me with where they wanted to have a *hierarchy of users for a different commercial purpose.
The basics should not be too hard to start off with metadata.. the subsequent administration and accesses might become a little more complicated.. needing overloading (or overriding) to Elgg functions.
I will post more thoughts later
( This is one of those topics that would go well on one of my techie groups.. ;-O)
I want to start with the principal that sharing passwords is a bad idea. I want the children to have their own passwords and the freedom to change them, learning password management is an objective. There will probably be an upper age limit of 12, kids get kicked out when they become teenagers. Then they can take off the armbands and join a different community.