About the bech32_hrp code, shouldn´t be changed when you change the adresses?
Why do you want so bad to change the prefixes? Have you tested to see if your altcoin is working? The prefixes/styling is secondary.
Also, in line 244, if I have to change that bech32 code, I have done it right? or should be another letters?
It seems fine. I don't cross my arms that you just change that variable and the “bc” prefix becomes invalid.