Although it is difficult to say why (luggage, meals, other special arrangements) Antoinette's ticket price is rather high. Thus high for an E deck cabin or a D deck one. I would presume she was somewhat higher possibly B or A deck. However I don't know much about her or her possible cabin location.
We know that a single lady occupied a cabin across the hall the McGough (which was E23). Fleggenheim is just one of the 5 or so single ladies that would have occupied a cabin alone. Since we do not know her cabin or deck she is a possibility, along with Candee, Lindsrom and some maids.
Daniel.