Blackwood is most likely going to be traded before the trade deadline once he gets healthy. The Devils going into the season wanted him to be the starter and that is not going to happen now. Then came along Akira Schmid and now Blackwood is trade bait so I would hang onto him and see where he ends up and what his status is. Gustavsson with MAF back is not really worth having on the roster.
I do think Demko will improve and when Frederik Andersen returns you will have a good tandem with Swayman on a very good team making a solid #3 goalie.