If you have to ask these questions, the answers to the first two questions are going to be no - it's not that it can't be done, but that it's not going to be a "financially viable project".
You're going to need a front axle with gears to match the rear (or both front & rear axles), transmission with transfer case, drive shafts, along with all the various trim pieces etc. (assuming that you want the finish product to look reasonably good), and unless you have a free donor vehicle to get the parts from, you're going to be spending a ton of time hunting parts down in junk yards. It's going to be time consuming and if you don't have the skills to do this yourself, you'll need to have deep pockets to pay for it, and it's probably going to cost you less to just find another 4WD.
