All four of them sound really natural. Excellent job.

All four sound natural to my ears.

Those are all good sentences if your intention is to draw attention to the developer. You have a choice: either you can 1. put the emphasis on the developer you are unhappy with, or 2. put the emphasis on what it is that you are unhappy about ("putting so close", "building so close") If you want #2, you could write "We don't approve of the developer's putting the factory so close." "We don't approve of putting the factory so close, as the developer has done." Since "putting" is the direct object of the verb, its importance is emphasized.