Upload & Sell: On
As was said, there is no dependence on the order, except when you are making copies. Once you make a copy, the processing of the two versions is no longer linked. For me, it makes sense to do initial organizing and processing of the images upon import so you can get a better idea of what you have. Then apply collections if needed.
I import images into a folder as a set and do the initial deletion of unwanted images. I then do initial ranking/keywording to finish getting organized and do whatever initial processing is needed. After that, the use of collections may be relevant. If it is something like a family event, they generally are just in the folder and I only make a collection of the select images I plan to post. If it is landscapes from a trip, there may be individual images that get added to various portfolio collections. If I have made copies to try different processing options, they are all in the original folder and the best copies may get added to a collection.
Generally I keep the images in folders by date/event name and use collections for special groupings of those images as needed.
One thing I am finding is that I am probably not using copies enough. If I have just the original in several different collections, going back to re-process will change it in all collections, which is not always what I want.