Missing Fuse

It may be for remote AC. Does your car have that?

 

Can I install remote AC if my pri didn't come with it?

 

Checked your can air filter recently?

 

I believe that fuse was replaced with a fusible link. The topic came up in one of my posts when my compressor failed at 81K in September last year. I asked about that fuse and was told it is now a fusible link.

The foul smell problem is addressed in numerous posts, given the proper search term. You might have a condensate drain blockage which will need to be cleared from underneath the car. If it is a blockage you can sometimes here water sloshing around when turning corners and braking. If it is not blocked you might be able to eliminate the smell by turning the A/C off (press the A/C button to turn off the green LED) while letting outside air continue to blow through the system for about 5 minutes before parking the car. This will ensure that additional water vapor will condense and flush the evaporator core, drain out, and the evaporator core will dry somewhat. This will reduce the amount of mold or mildew growing in the system. You will have to perform this flush operation for a couple of months maybe. If that doesn't work, then the next step is a chemical flush. There are various products and procedures, and it might be best to trust this to the proper technician. Good luck.

 

My guess is that you might have a different wiring from your fuse box layout info.
For example, I got the same thing on number 15 as you ECU-B3 and 14 is "no circuit" but here I found that:
14 is ECU-B2
15 is no circuit
and 16 is ECU-B3
Toyota Prius mk3 FL – fuse box (europe version) | Auto Genius

Also Air conditioning system is under 15 in the main layout and the "Left side" layout it's second time under 23.