These cars are fairly robust, excepting the transmission and if you take care of that it should last as well. The problem with asking these open-ended questions is you are going to end up with 100 different opinions, all of the different. Or, you will end up with a couple of members saying its already been asked and answered.
I would follow the manual for fluid types, but use your personal preference when going synthetic or dino. Its not going to make much difference with the 1st Gen Explorers. The only few I have a personal opinion about from personal experience is using Type F in the power steering system, and flushing it out every 3 or 4 oil changes, and using 85-140 gear oil, just because we live in a warmer climate.
I have had my 1994 since late 1995. It was a early lease return with only a few thousand when I picked it up. It now has 187,000-ish miles. I have gone through two OEM transmissions before I put in the 700R4. When I did that, I used a NP231 transfer case because it was manual and almost free. In 2013 I swapped the front axle for a high pinyon D44 and 14" coil overs. A short time ago I installed a Atlas II transfer case. Engine is finally starting to feel its age but still runs good. I have a spare engine that I am thinking of rebuilding, but might swap in a GM supercharged 3800 V6 L32 SIII because it has the same bolt pattern as the transmission, and has more HP than a 5.0, but not enough to tear up the axles, and is a very reliable powerplant with great aftermarket support.
Here is what I have in the Explorer currently:
Engine - Castrol synthetic 5w-30 with Wix filter, cheap on Amazon. I change the oil once a year so its only a few thousand miles, and use whatever I can get the best deal on.
Transmission - Valvoline Max Life multi-vehicle, but I have a 700R4 GM transmission. Don't remember what OEM takes. Best way to take care of a transmission is to change the fluid at least twice the recommend interval. I got this from the guy I have paid a lot of money over the years to rebuild/repair transmissions.
Transfer Case - Amsoil MTG GL-4, but I have a Atlass II transfer case. OEM takes plain old ATF and I would recommend Mobile One just because of infrequent changes.
Differentials, Lucas 85-140, because its recommended by my locker manufacture (Eaton). Before the lockers I ran Valvoline synthetic for value, and availability, and it works.
Power Steering - Ford Type F because I got a deal on it on RockAuto during a close out. I have at least 5 quarts of the stuff for later. I used to run Mobile One ATF because it quiets older pumps and can handle more heat. I recently replaced my pump with a reman, and the steering box with a RedHead and went with their recommendation. I also have a remote plate cooler in front of the radiator. If you have the original pump, or just a old one, you can use Mobile One ATF and the whine will go away.