No, please don't overlay closed ways onto other features (walls, fences. etc) - it makes it very hard to select the correct way to edit, and tends to end up with users adding nodes to one of the ways and getting them out of sync. A principle of data normalisation is to not duplicate information in a way that can get out of sync - if a wall performs the function of a boundary, then it should _be_ the boundary.

I do see your point about changing land usage, and that's a cogent argument for maintaining separate relations per field.

I'm hoping we can produce the best of our combined work, as we have both spent multiple hours editing this area, and it would be a shame to lose it.

I do see now that the later-removed ways that missed the first pass (under the walls rather than above them) were differently tagged - I'll fix those up immediately.