I have seen this issue on this forum. I have not seen the problem. Do a search for "soft on one side". It seems to be a tolerance issue with the lens mount and not the lens itself.
Yes you remove the hood from the X5S. Depending on the ND filter you bought you may have to remove the balance ring. Best way to do it is just install the filter then check balance
Inspire 2 | Custom Filter Sets
very little color alterations. 46mm Not cheap I use them on all DJI 15mm, Olympus 12mm,17mm 25mm and 45mm ( Step-up ring )
Did you not get the box when you bought the controller? The shipping foam should fit in the standard spot in the case. I may be wrong but the Cendence Remote did.
Depends on the firmware update. If one set needs it when you are done with update then all will need it. The update notes posted will tell you if it contains a battery update. It does not take long.