I figured out the selling junk thing but didnt realize you just cant get a job. Do you happen to know where to get the lake and muddy water?
For the bottle, you can buy the "plastic bin" in the junk shop (glorified name for a bottle, I know),
Now, to get the muddy water, just explore the neighborhood on mornings and afternoons (haven't got that scene to prop up at night, so can't confirm if it happens or not),
To get the lake water, you gotta explore the park at night (random chance, so stock up on bottles before doing so).
I think the only cum you get without buying it is the rat, hose and bottle of cum, the rest you buy on aero's shop.
Go to the park, you will see him again there and based on you route with him (sub or dom) you have different scenes.
Again, you can see the fan wiki, a lot of the events there is accurate. And you can see the drop of every local