My last idea/suggestion for a fix, was by routing the edges true and parallel, grooving them to accept a spline, then tapping the edges towards each other.
After routing, there would be 4 small radiused corners to contend with where the router meets the edges of the unaffected planks. A 1/4 inch bit would make a 1/8" radius. There would be 4 radiused corners to contend with. Two on each side of the repair area.
What if cleaning and straightening these tiny radiused corners took an additional 15 to 30 minutes
each, using a Dremel tool, small files and a utility knife? An extra hour or two of surgery? So what. We're talking about saving a floor to avoid a very expensive replacement.
When they come back for the spring and season, I'll have to go back down there to refresh my memory a bit before committing myself to the project.
Best was to do the routing of the edges would be to temporarily hot glue my a straightedge to the floor as an accurate guide, then true up the corners, then tap em together. ...right?
If anyone has a better idea, I'll gladly give you their phone number.