You know, I treated your situation just as if it were at my store. The only thing I'd do differently, and I don't know if they did or not, is go that extra mile to find out what the difference is. I even asked a tech and in theory, a new reman unit should have all the updated information. The question is, when did they come out with the reman unit? before or after the bulletin? The two bulletins pertain to specific complaints and codes, so if you came into my store with one of those, or vehicle exhibited the code on the bulletin, I would have my tech open the tech case, because I would want to know the answer. So as it stands, I cannot blame the dealer for siding on side of caution. Let me just add one thing here, the profit margin on the two is relatively the same. By that, I mean that it would make no difference to me if I sold you the more expensive or less expensive one, the margin is realatively the same. In fact, if I had the option, or if I could, I would go for the less expensive one because I would stand a better shot at selliing a $600.00 computer than a $1600.00 one.
With all that, the 89661-08061 would work. Keep in mind that just because your computer did or did not fall in lines with the TSBs, doesn't mean that the compurter you get from the junk yard will or will not. Again, the TSB states the optimal word "some." After you install the junk yard computer, you'll have to drive your Sienna around for a bit so that the computer can re-learn everything from your vehicle. Even at that, you do stand a chance of having a bad used computer. It is a gamble, but hey, $70.00 is better than $1700.00.
I really do wish I could be of more help, but I am limited by certain variables, etc.
I hope what I have done gets you somewhere.