My anomalous results problem was solved by enclosing a block of return elements in a single div instead of returning them as a comma-separated sequence of elements. I have no idea why that works, but it does. (Basically I have no idea why the sequence was failing, but no worries -- problem solved, and the changed approach is actually simpler.)

So now I have working search results, with plus, minus and quotes already functional. All that's left is the long-s substitution, and variant-spelling generation. I also have to figure out how to tag the results in the actual pages when you navigate to them.