Regarding your hotend order, I am afraid you need to come to that conclusion yourself 
We do not know what Snapmaker will do with our findings. If I were them I sure would do something since I would want the J1 to be a success, but it is up to them to decide if and what they will do when. For now, I guess the Snapmaker development will carefully read our data and try to confirm our test results.
I decided for myself that I want to have full use of the printer as soon as possible, therefore I invested a part of what I saved from being an early buyer into a full set of parts for all my hotends.
Regarding the beating sound, I am unsure what you mean: if you mean the “clack-clack” sound coming from the extruder: this will be solved by the improvement.
Apart from that, my J1 never produced any beating sounds - I guess this is since I lubricated its linear slides as the very first task upon its arrival and then let it run slowly until I was sure the grease was evenly distributed in the sliders. Therefore I am afraid I cannot help you with that…