I think that's the course I am on. Disappointing for sure. It drives well and now that I have replaced the aux battery, it starts reliably…unless I do an ODB scan. The fact a simple dis/reconnect of the battery should be a clue as to where the problem is. I keep hoping there is something that's been overlooked, some component that will resolve all this. But without a motivated dealer, there's not much I can do. They charged me USD1600 to dry it out and do their weak diagnosis so I won't be seeing them again. Toyota dealers won't touch it though it's essentially a Highlander underneath.
Time to take some pictures and clean it up, I guess.