I've already placed down 3 in 1 lots on all my maker lots, it's so much easier! I'd definitely recommend it.
Also AliSim19 I went with your idea of selling the dumpster dive items at the 'dock' area, had the same weird effect as you with the surrounding area looking all... deleted? But it worked!
...until, unbeknown to me, that specific neighbourhood had the caring is sharing NAP and a sim kept stealing my till. Took me 3 tills until I just had enough and decided to lock it in a room :'( :D