1. Tracked overflow items don't increment the page's memory footprint.
2. Split-merge pages created by reconciliation aren't reflected in the current page's memory footprint. Because split-merge pages stay in memory in order to support future eviction of the page, they should be part of the page's memory footprint. Note, the memory footprint should increase/decrease each time the page is reconciled, as previously created split-merge pages are discarded on each new reconciliation.
3. Split-merge pages created by reconciliation don't have their memory footprint set when they're created. As split-merge pages can't be evicted, this probably doesn't matter for eviction, but it does matter for overall cache size.