+1 on propshaft removal being a dead cert sign the car has transmission troubles.
The VCU will have siezed and this will definitely have trashed the bearings in the IRD and good likelyhood there are teeth missing from gears in the IRD - the crown and/or pinion gears driving the rear shaft. If its quiet in 2WD, then probaby the reamining gears are OK. It may also have done damage to the rear diff, although reading the various tails of woe, this is not quite so likely.
So, if you're buying a 'cheap' 2WD with the intention of just bolting the props back on and enjoying 4WD - it aint going to happen!
Having said this, you could buy a 4WD at a top price that fees and sounds OK, but has had the beginnings of the VCU siezing and its just about ready to go 'bang'. There are tests on described on this forum to test whether the VCU is working OK or not, but I have my doubts about their accuracy and especially if you have nothing to compare against.
So that takes us back to 'cheap' 2WDs. In my mind, the best way to buy a Freelander could be to get one that is in good condition, but is being sold cheap because it has transmission problems. If you factor in the price of reconditioned VCU & IRD to start with, you should get a good reliable car. This does leave a doubt on the rear diff, and its probably worth getting VCU bearings as well, but if you fit it all yourself to keep costs down, it may be the best way of doing it. Make sure the car comes with the original props and buy parts from reputable suppliers - if in doubt research on here or ask Q's.
I've just been through the process of replacing the IRD, and if you've got good access (I've got an inspection pit) its not very difficult. Iin fact you can't get reconditioned units over here, so I had a bearing kit sent over from the UK and got a 'diff shop' to install them in my IRD. The kit was about 130 quid and the shop charged me about 300 quid.
In my case, I'm pretty confident the car is generally in good condition. We travelled about 400 miles over a couple of days with a tyre that had deflated a bit and went unrecognised, and that trashed the IRD. If I'd sold it as a 'cheap 2wd', it would have been very good buying!