Nice to have you with us. Not sure all that organ meat is the way to go. Toads and minnows are a big no, no. Those two item can carry parasites and the minnows also contain thiaminase. The danios and tilapia are fine as long as the tilapia isn't a product of China. Have you tried night crawlers yet?
Here's a link to the forum care sheet. Feel free to ask all the questions you want.

Garter Snake Forum - Garter Caresheet

New member welcome - Garter Snake Gallery