I agree that using white arrows (or circles) would address one of the limitations of option-3. However, the bigger issue with option-3 (the judgmental issue) is still not completely addressed.
For instance, is the interest rate a “good” indicator or a “bad” indicator. How about imports ? Should they get a green background or a red background ?

As discussed in the original post, sometimes it is good for the interest rate to go up, but some other times it is better for the rate to go down and it is hard to pigeon-hole some indicators into “good” and “bad” categories.

So overall, it seems like choosing option-4 was the right thing to do. As you note, UI design questions are often complex matters. So the choice of option-4 is debatable, but for now, it seems to work fine.

The actual image-part in the icon (an arrow shape in this case) is useful to people who may be vision impaired (say, color blind) and cannot distinguish between various colors.

One solution that addresses both might have been to add an icon background and have that background take the colors red or green. In this case, the arrow would remain white (or an appropriate color with sufficient contrast) against the colored background.

Overall, you’re right – Choosing the right icons is a complex problem and requires a lot of testing and making many considerations. If I were hiring a visual designer, this speciic scenario might be a great interview question

Some of the indicators in the “Business” section of the app (like Industrial Production Capacity Utilization etc.) may give you an early indication of market demand. Others (like Manufacturers’ new orders:Durable goods) may also be helpful.