A good set of tyres will make a big difference (but that might take up your entire budget), I have been using Coopers ST-Maxx for years, done about 80,000km on them across the country and they are only starting to slip on soft sand now. I personally wouldn't bother with replacing the wheels.
A good 12v system would be a bonus, but to be honest the quote for the Enerdrive system sounds expensive; find a good auto-electrician and get them to put you a RedArc system together and you should save a few dollars.
UHF is good for communicating, I have always had them but now with expanded mobile networks and satellite phones they are becoming less used. Maybe look at a Garmin inReach device (or similar), great for tracking where you are going and they give you the ability to contact people if something goes wrong; and if it really goes wrong its got an EPIRB type functionality.
I wouldn't bother with a winch, just a set of MaxTraxx (or similar); but if you do go that way consider keeping your alloy bar, the weight of the steel bar and winch may require some more suspension fiddling.
Other than that, if you are committed to using the vehicle for this purpose (just because $10k is a lot of money) a custom canopy would be great, especially for your new electrics. Having an easy to use set-up where you don't have to climb in the back all the time will be great for when you are stuffed at the end of a long day.
The main thing will be to make a plan for all you want to purchase so that if you do need to make a change to the suspension you only need to do it once.
Hope this helps.
2013 Toyota Hilux SR5
4x4 Manual Diesel