I think you are going to run into a few challenges doing what you want. The CWOP uploader uploads a fixed set of obs, if you want to change this you will need to modify the CWOP uploader code in
weewx/restx.py (refer
class StdCWOP and
class CWOPThread). There are no user configurable options for limiting the uploaded fields. I have no idea if CWOP will accept a cut down suite of obs, CWOP is not a service I use nor am I familiar with it.
In terms of removing the 'weewx 4 simulator' comment, this is hard coded in the CWOP uploader (WeeWX, WeeWX version and station type). Station type is picked up from the driver, so you either need to find a BME280 driver (you have a BME280 service witch is quite distinct from a driver) or you need to change the CWOP uploader code.
If you end up modifying code I strongly suggest your final solution involve sub-classing the CWOP uploader, this will prevent future WeeWX updates possibly overwriting your code.
Gary