A few doubtful nginx directives. Pls help.

I was following this DO article: https://www.digitalocean.com/community/tutorials/nginx-location-directive

And have these doubts regarding nginx conf files directives:

• What if there are 2 non-regexp location blocks: having /t and /s and user types /f, then which location would be served, and why?
• If a location directive has ^~ /somepath prefix, and the visitor has typed example.com/some then would Nginx stop searching even at this partial match? If yes, then it’d stop at / matching also? If so, then why that conf file should’ve any other location block at all? Because in any case, / would be matched at all times, then why bother having any other locations?!!
• When a user types sub.example.com/somepath/?user=any then what exactly is $host and what exactly is $hostname in it?