Your XJ should be able to pull that Supra fine as long as you aren't hauling it long distances. For around town it will be fine, just plan ahead and don't try to rush. But with that single axle trailer you will be very tongue heavy and you will certainly feel every bump.
That's a lot of weight for that TJ man. Even with the lockers and the 44, if it's a 5-speed you could cause the clutch to strain itself pretty bad. I know mine can tow my boat as I've towed rigs 3 times my size. But that's a buttload of tongue weight. I know I'd be squatting on the bumpstops with that big pig.