Unfortunately the hot pink garter died. I didn't know anything about brumation and she died while I was brumating her. This was 2 years ago.

A dominant trait will prove out in the first year of breeding so this isn't necessarily true. I agree that it is a normal but none the less selective breeding could produce a killer looking snake. I would be curious to see pics of a hot pink snake.... I just don't believe it....
I don't know of any dominant garter snake morphs though.