@red_bean_casserole
"Myaaster"
Simple as that, you got it. Ignore the honorific, as it's less of an honorific, and more of part of an entirely separate word.
ご主人 = "Husband"
ご主人様 = "Master"
Then she's just being cutesy, and is a cat maid, so "Myaaster" comes easily from there.
Additionally, are...