Think your plan to re-con another 1 and then swap out is a good1, i face the same issue and thats my plan, its a 1st 4 me 2. I kept a dead siii for 10 years knowing 1 day i would want bits, got a sII 2 months ago(with a series III box) n all that shifting the old LRO around seems worth it now, it also jumped out of 2nd before it died,
Post any hard earned leasons you learn, wish i could fit an auto but i have a Daihatsu 2.8 lump in it, n dont think there is a conversion available, love the motor tho,