Strategically, the first thing to determine is the data aggregation that makes sense to your directors. For our business, sales territories roll up to business units - and a common sales territory unique ID exists in every application. We summarize data at the sales territory level in each application (by count or sum) - and then sync that table across to the central dashboarding application - and then summarize to business unit as needed. This serves two functions - one it limits the size of the sync tables, and two, it optimizes quickbase�s single thread architecture (If you build table relationships to the children apps, you combine everything into one server process and kill performance - so direct table relationships are a big no no).
At this point, if you need the ability to quickly drill down or jump to the underlying data in a child application - use formula-text fields that feed a variable to report in the child application - or formula URL fields. (Same as above, using report links will hurt performance)