Sounds like you got bitten by the bug, like us all. They are fun trucks and once you get one it is hard to let go of them. I have owned mine since 87, before you were even born. lol Some here have had them longer.

The balance shaft removal is a 50/50 decision here in the forum. I have decided to leave mine in during a very recent rebuild, but many have removed them. This is a choice you will have to make your own. They were installed to keep engine vibrations down to a minimum throughout the truck, mostly in the driver's butt. 4 cylinders have a typical vibration and Mitsubishi installed this to smooth them out.
If you decide to remove it, it would be best to start balancing a few items though. This will help counter balance the removal and help to compensate the increased vibration. You should balance the flywheel and maybe machine it to remove about ten pounds. There is also the balancing of the pistons and rods to achieve matching weight throughout the 4 of them. A crank balance would help and I'm not sure if anything else would need to be done. Though someone will poke in and add the info if they read this thread.
Some people just removed it and deal with the effects. Some feel the effects and some don't, so it's an owners choice. I would check out the internet also. Check through google to see what others did and what they liked and disliked. Remember all trucks are not alike and your will most likely run different then if I did mine and compared them both. Kits are about $15 or so, but the engine must come out to make the change.

Your head, if it is crack between valves is what I would say 100% fixable. It would be beneficial to do that and it shouldn't cost near the cost for a head. Remember if you buy a head and have it shipped, shipping is not going to be pretty. Figure $50 to $100 more for that. Plus if there is work to be done to a head you had shipped. That money could get yours fixed. The head on mine is a repaired head and it has lasted for years.
These trucks are notorious for cracking heads. The 2.6 seems to be worse from what I have heard. There are ways to prevent it as best as possible and 80% is normal maintenance and paying attention to your gauges.
The head I have is not what you would want, especially that I have no idea what shape it's in. I wouldn't feel right about selling it if it was NFG. I was just saving for a project or something if a shortblock ever dropped into my lap.