I’m starting to realise that AE is a “different beast”, but this kind of shuffling of timeline data seems pretty fundamental to me – thanks for the advice though Dave.
If anyone else is wanting a similar solution – the best solution, well that I’ve found is to seperate your file into several seperate AE sequences to make them more manageable when making timing adjustments, then use another AE file to comp the renderings from the others together, then each complex sequence can just be a simple piece on one layer.
That said, this is early days for me with the app, so I’m sure there’s probably a better option for a better workflow for updating nested content like this that someone else can suggest.