The main problem with removing these items is you have to open the whole phone, which is sealed. If you wanna do this I recommend you give it to an actual repair person with professional equipment and experience to do it. It might cost you somewhere around 60-100 dollars. Breaking the water seal is not that important IMO.
you don't really need to remove the cameras because cameras can easily be blocked with black electrical tape. This leaves you the option to be able to use your camera when you want to. Electrical tape works pretty nicely.
Microphone and speaker are more difficult to mask as sound penetrates everything. So if you want that kind of assurance of security then its best to remove them entirely. These 2 components are rather easy to remove or disable without removing (cutting wire), but still require to open the phone.
The other sensors like accelerometer, barometer, and compass, do you really need them removed? I don't think they'll do you that much harm. Also removing them might be more difficult as they might all be packed together (and with other components) and close to critical components. I can't comment on them. Same goes for GPS. Remember, your location is always tracked using cellular triangulation, removing the GPS may not make much difference.
I would say don't worry so much about the other sensors (Although its your call). But mic and speaker could be disabled/removed, and a repair person could do it for you. But I would say don't do it yourself. You can also consider buying accidental damage coverage for your phone so if the repair person damages it maybe the accidental coverage will cover it.
This is all "IF" you think removing these is really that important to you.