After all this I'd be glad to hear more about your league, a list of champions, a fictional origin story... maybe starting a thread on this board somewhere will help you start this project. Kind of wish I had for my league, and maybe I will for my next save.
The name and concept for Tunas comes from
jag224's league. Your classic giant saguaro cactus doesn't grow there. I love these prompts for that reason - why else would I have read about the Chihuahuan Desert?

the prickly pears look OK to me, but I wanted it to look like a baseball glove- I'll be using it for Guadalajara I think in my league and it can be improved, or a border added.
I'll make a little distressed small red logo. Surprisingly hard to find illustrations of Sichuan peppercorns- I thought maybe something like the logo of our
local restaurant .
Bats is good. It'll make me resurrect my frustrating/abandoned Austin Bats attempted logo.

and I found a Bulgarian reindeer stamp last night lol, so the Caribou should eventually come into existence