Having owned an few XJ's, 3rd and 4th gen 4runners, and an 80 series, I don't think I agree. This may be an unpopular opinion, but as much as I adore XJ's it would be the last on my list of recommendations for what you're talking about.
Using a 4th gen 4runner as an example, the rear hip room is 55 inches, and an XJ is 44. 11 inches more interior width is pretty noticeable, especially when sleeping in the back with the seats folded. I also owned an 80 series and spent a lot of time sleeping the back of that( (I'm 5'7") and found it pretty comfortable, and the floor was flat which is a huge advantage
My 4th gen floor was not flat, but i built a cargo platform that replaced part of the rear seat and it worked well for sleeping inside. A friend of mine who is about 6'3" slept back there and reported it be comfortable and roomy.
I think any of what you listed is going to be tight with two people and gear (depending on how much gear you carry), if you build a platform to sleep on stash the gear below that would help tremendously. I've slept in 3rd runner, 4th gen runner, and 80 series with myself and a smaller female (5'4") and we had to move all the gear to the front seats, and some of it to the roof rack on longer trips where we had more stuff, again, a platform that elevates you and allows gear below would be the ticket for trying to keep everything inside. If you have a medium sized cooler or fridge, that will be challenging. I've spent some time in the back of a first gen sequoia that would probably be my choice as the most spacious for sleeping, but as you pointed out, it has the least aftermarket support.
How big a vehicle feels on the trail is entirely subjective to the driver and the trail, what feels huge to some, may be fine for others. The same with ride quality, but for long jaunts on pavement, and dirt roads IFS wins, and the XJ loses. After spending a lot of time in my cruisers, runners, tacoma's I test drove an XJ for old time sake and it wouldn't be my choice for any sort of "comfort".
For running 33's reliably: again, the XJ loses here. You're looking at 3 plus inches of lift, crappy control arm angles (or long arms), gears (most likely), upgraded steering and brakes etc. The 80 series has a drive train that's rather large and overbuilt, and can easily handle 33's, but the mpg was never good to begin with, and won't get any better with larger tires, the 80 is also rather slow by modern standards. A 05/06 sequoia with the slightly higher HP and a750F trans (5 speed auto) will turn 33's easily, even on stock gears. The 4.7 is a fantastic motor, and the same rule applies to the 100 series LC. Again, having driven both I would take the later 100 series with the 5 speed, and it could easily handle 33's. The 100, 80, and sequoia all have a larger drivetrain, including brakes, that would facilitate "reliably" running 33's. Park an XJ next to an 80 series and compare the size of the axles, brakes, bearings etc. A 33 isn't huge, and if you're not running harder trails, but if you want reliable, a part that's less stressed running a given tire size has the advantage.
It sounds like your biggest factor is what you have access to in your region; choose your compromise wisely.