Optimal journal publications strategy (academic career)

the 'working paper' notion in economics appears unique to that area, so I can't comment on that. The problem with your phrasing though is that it ignores quality issues. Assuming therefore, that the 10 papers are fixed, and the only question is which of the three options to use, then the answer is probably (1).

For people who want to know about the work, either of (1) and (2) are fine, and (3) makes little sense (I also don't understand why that would be viewed as unethical). but even then, there's some low-quality non-zero positive information associated with publication in a journal the reader hasn't heard of.

For people who prefer to look at CVs to infer quality, then (1) is superior to (2) (again (3) doesn't make sense).

One way in which (2) is superior to (1) is if you're hoping that you get the benefit of the doubt for unpublished work that has no "quality signal" like the name of the venue it appears in. This is unlikely to happen unless you're in an area where it's common to have unpublished manuscripts circulating and valued.