You raise some very valid questions. The factor of increased wear to the vehicle should indeed be considered. Less so if you are able to maintain the car yourself.
In my limited experience, I've found that bump starting in 5th gear is a lot smoother than trying in a lower gear and seemed to minimise the 'shock'!
De-clutching or coasting in neutral with the engine idling could be safer and a bit less wearing to the clutch, but with a lesser return.
Circumstances vary - so 'you pays your money, you makes your choice'...
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