Sounds good. In my replay of the first 30 game days yesterday, I didn't interacted with Alan (the drunk guy) either. However, I did get the cut scene for the cashier.
When you said "Sometimes I can shop for quests when they play a cut scene upon entering the shop. But never during free roam." I thought you meant during this playthrough you had already shopped on quests - but you can't even start "shopping" until after that Darnell/Natalie cut scene.
EXCEPT - it sounds like - if you advance too far into Mary's quest line (the scale) --- or, probably Clara's too (the printer card) --- before first visiting the store. Those cut scenes must override priority on the introduction to Natalie cut scene.
Which, based upon your quest tasks AND you saying you have already seen the cut scene for the scale (and bought) makes things clearer now. One of us will test that ....
APoc1 !!!! Calling
APoc1 to Aisle 4, cleanup!