Walt: LSI?
Jesse: SEE?
Gus: ILI? Only problem I have with this typing is that he and Walt seem to come off as pretty much the same to me. And I don't think he and Jesse would be pals lol
Hank: ESE?
Marie: EIE?
Tucco: SLE
Clean Up Guy: SLI?
Saul: ILE?
Jesse's GF: IEI?

I haven't really thought these through, just kind of throwing some macaroni at the refrigerator here.