Couple of questions - with mobx-state-tree are there ways of handling side-effects nicely? E.g. an equivalent to redux-observable epics (or redux-saga sagas)?

In regards to #5 redux there's a pattern to use selectors (which can be memoized with reselect), which means that whether components update is a simple shallow === comparison on their data props, and also a handy abstraction for getting data out of a potentially deeply tree and applying transforms to it.

#6 looks interesting, though.