It's kind of hard to answer. About the only thing that is a safe buy and useful no matter what you decide is the winch. The locker is useful, but if your final decision ends up wth tires big enough to warrant a gear change you're redoing work you could have done only once, and paying for it. If you do a lift now, with tires as big as you intend to go, you can do a locker and gear change at the same time. But if you do that lift and later decide to go the ujoint route you've wasted time and money on a lift at least half of which is not transferable to a ujoint conversion.
I think the first thing you have to decide, in order to be as money efficient as possible, is your final goal. If you do a 2x4 lift and change your mind, you've wasted money. Do you need a 4x4 conversion? If the answer is no the next question is do you want one anyway? If that answer is yes the next thing to do is call Chris at ujoint and tell him you need to piece it together, and how to do that with as little down time as possible.
I think the bare minimum you can do if going the ujoint route and wanting to get it lifted soonest is the ujoint lift for the front and rear, which will require you to buy the complete lift and a front axle. Transfer case, transmission, and driveshafts can be handled later, but in the mean time you will have a lifted van you can drive.
I think you might be hard pressed to get away with spending $1000-$1500 to get off the ground, without the risk of some of it being wasted should you change goals mid stream.
No matter what, I'm sure Chris can explain the ins and outs much better.