Hello and thank you for posting your concerns. I am not from Enderby nor have I ever mapped there. 

I apologize for the messiness of my area drawing. I will be sure to rectangle it where I can in the future. My methodology for land uses is such for small areas such as what was mapped here: I draw a residential area around all of the development and then draw commercial on top of that since it usually takes precedence in rendering. I have not seen any particular style guide for this but it seems to work. I once again apologize if this is not permitted.

I know that something is most likely commercial from satellite imagery. If it is in the “boxy” style of low commercial buildings, it has a dedicated parking lot, or it has additional features that are of business, I think I can safely assume that the building is most likely commercial. 

I have not seen any official discussion on this mapping. I have been doing this of my own accord. If conducting large scale land use mapping via satellite imagery is not permitted, I once again apologize. 

Overall, I am not sure of the agreed on convention for BC, I usually look at the OSM wiki or look for regional examples.

I hope this answers your questions.