I think reparations could be spent as they see fit. Reconstruction implies the money is going to exactly that.

But I agree it's a weird nitpick at this stage, as it seems almost impossible to verify once in place

No, the point is that instead of the US paying reparations from their own pocket they will allow Iran to tax Gulf countries.

That sentence is just worded badly, I would rewrite it as:

10. Iran to use Hormuz fees for reconstruction instead of demanding reparations from the US.

I think you're right, it's a bracketing ambiguity.

Rather than "Iran to use Hormuz fees for (reconstruction instead of reparations)" it's more likely to mean "Iran to use (Hormuz fees for reconstruction) instead of reparations"

Yeah, I think they want to do it this way, because Iran wants some compensation for damages, but paying reparations directly would be too humiliating for the US, and Trump would never agree to it.