I say...
1. Pajero
2. Pajero
3. Sorento
4. Sorento
5. not sure, but any difference should be insignificant
6. Sorento
7. Sorento
Pajero is nice and durable, but not the most comfortable and is the weakest among the three. A/T 4x4 gets the worst FC, similar to current 3.0L CRDi's (except the frugal 4JJ1).
We had the Trooper before. Even if the 4JX1 is a piece of crap as you put it, it has stayed with us for eight years from 20tkms-73tkms. Have replaced the injectors (free), turbo, center link assembly, and throttle position sensor (free). Engine is very punchy, though gas mileage is just so-so at around 6.5km/L. Ride comfort is quite good for an SUV, though there is a significant amount of body roll in turns. The truck-like recirculating ball and nut steering is rather bothersome as it takes about five turns to turn from lock to lock, though it is very light to turn. Everything else besides the engine is very durable. We have never replaced any suspension parts. So you are OK with an engine swap? 4JB1 would make it underpowered. If you're getting the 4JG2, performance is similar to the Pajero, so you might as well get the Pajero instead and save the hassles of having to swap engines. The 4JJ1 is a nice proposition. Fuel efficient and decently punchy engine in a good looking car (and not the hearse-like Alterra

). That is IF you can get your hands on one.
The 1st gen Sorento has a smaller but more modern engine (same as the one in the Starex GRX, if I am not mistaken) and a 5 speed tranny, which means that it is more fuel efficient than the other two. The tranny's a different unit than the Carnival's, and I have never heard anything bad about it so far. Local models have no 3rd row seat, but I think some KDM units have them. There's nothing really wrong with rack and pinion steering. Many AUVs use them, and they are very durable indeed.