I would view it from a different question.....
...... "which would make me happier, within the timescale that I have?"
What I mean is that the jobs you list (and more) can be done with the engine in or out..... it is certainly easier with the engine on a stand in the garage - but it will take a longer timescale.
That said, if timescale is less important, you will actually achieve far more with the engine/gearbox out, because project creep will rear it's head and you will be cleaning, painting, replacing lots of parts that you couldn't see or reach previously (both on the engine and the bulkhead areas).
Bear in mind that the workshop manual nearly always takes the line of getting a specific job done in minimum time (for dealers and customers) - even if it would be easier with the engine out, it won't write it that way.... but only if it is absolutely necessary. So, assuming that you are doing 3 different jobs now, none of them will individually tell you to remove the engine, but to do all 3, it is actually quicker to do so.
(If I didn't need the car 'soon' I'd take the engine/box out and do whatever I could before having to put it back in!)
