im pretty sure these would have an electrical oil pressure guage standard, so yeah find its sender and connect your new guage to it.
For the oil cooler, Yes u can use a 4ag one on it, you need an oil cooler sandwich plate (goes between block and oil filter). gze's never had one standard, but some 4age's did (u can get these from an auto shop new for around $50, just make sure ur asking for one to suit a 4age, casue they wont find one for a 4agze. + then an oil cooler core + lines and fittings, then just mount it where u desire.