We have decided to remove the flooring back there, it was a hard decision but it has so many issues that most of it is unsaveable. There is rot from generations of leaking sinks and water heaters, they had glued Luan plywood down and since we need to replace some joists anyway it just made sense to take up the old floor completely. We are replacing it with 2x6 tongue and groove pine flooring, as close as we can get to the original while staying within the budget. What flooring is salvageable I am thinking of turning into cupboard doors.
Here is a short video I took of the kitchen, I just couldn't get pictures to show how big and bright the space is now.