Is there any mathematical probability of a certain character of the hash. It can be one of sixteen correct? (1234567890abcdef) Or does a number have more probability than a letter?
As HeRetiK said, hash is a number. For better visability it is showed in blockchain in HEX (16 base). But for computers the base is not very important, however the lowest level is bit (2 base number represented by 0 and 1).
Answering on your questions, yes, the probability of each symbol is 1/16 (if you use hash repsented in HEX). But if you use hash in BIN for example, so the probability of each symbol will be just 1/2. For hash in DEC (10 base) the probability of each symbol will be 1/10. Etc. It does not matter which base you use, the probability for the whole number will be the same
For example, the hash fa1be5 (in hex) can also be showed as 1111 1010 0001 1011 1110 0101 (in bin) or as 16391141 (in dec). These are all the same number, just represented in different bases.
