I have a similar tractor ('89 Ford 2810) and have used Rotella 10W30 engine oil, ISO 46 and 68 hydraulic fluid and the New Holland "134" (what the NH guys call it and what they will recommend you use) New Holland 134
and a generic 10W20 THF (trans hydraulic fluid) from Tractor Supply. They all worked equally well for the most part. I think if you look up any of the UTF (THFs) you will find they meet the specs you listed
I have rebuilt my steering system (which is almost the same as an older 4000) and it's really nothing special. Crude, actually. If you live in a hot climate, tend towards the heavier stuff, especially if you have a loader. My tractor has a loader on it, which puts a big strain on the front end and steering. Until I rebuilt the unit, the lighter grades tended to seep past the seals more.