If check50 passes all it's tests, does it matter how you got there? More specifically, I could not figure out the modulo 26 on Hail Caesar. Using basic math and a few if and while commands/loops, I was able to achieve the desired result. Will my grade be lowered because of this?
No, it doesn't matter and no, it won't affect your grade. The interesting thing about computer science is that there are many possible solutions for every single problem. Your first priority should be to find a solution. Your next priority is probably to improve this solution or maybe find another better and more efficient one.