Two of those circuits use the headlight switch, turn signals do not.
I would start where you know there is power and then follow each circuit until you get to connections that have no power when they should.
If it was me, I'd start by testing the horn or measuring voltage at the alternator stud with the key off.
Voltage at the stud means there is a connection through the main splice. We kindof know that because the car starts. Blowing the horn sends power to the horn relay. That's better proof of a good connection. Observe the ammeter - it should go to discharge with the horn blow.
Then check for voltage on thealways hot buss of the fuse box. Then check the output side.
Now here's a problem with voltage checks. Just because there is a connection doesn't mean its a good connection. When current tries to flow througha poor connection there is resistance. You won't know there is resistance until turning something on. Lets say the fuse has poor -oxidized contacts. Turn on the parking lights and the votlage on the feed side fuseholder is 12.3 V and on the downstream fuseholder is 6 Volts. Now we know there is poor connection. (This was a recent FABO diagnoses)