My wife asked me the same thing, pretty much – she forgot to daven mussaf and after lighting, she asked whether she could still daven mussaf since it was before shkia. Unequivocally no, since – for a woman – lighting means accepting shabbos, and it’s either shabbos or not.
In either case, a tashlumin would be a regular plain shabbos night maariv. And, keep in mind, tashlumin can only be done right after the regular shmoneh esrei…. not hours later.