I don't know much about Ralf myself, but i still think we should keep Lingard. Of the midfielders that are considered to be more attacking, Lingard is the hardest working one, he offers something different than the others, and i think in a system with more focus on pressing, a Lingard type is pretty useful - and he seems to be kinda happy with being a rotation player, as long as he gets a decent amount of minutes.
If i was in charge, i'd rather try to get out Martial - together with the other ones you listed. We have plenty of wide players now with Amad and Pellistri behind the first team ones, Martial could bring more money in too, i think.
Doubt that much transfer activity is realistic in january, though.