Hydro 83 project

I have a 1982 IH Hydro 84 with 1,210 hours showing on the meter. This tractor started its life for the Port Authority of New York/New Jersey and then was purchased by a commercial plowing company where it loaded sand/salt into trucks in the winter. Starts right up and runs strong. I am a newbie to tractors. I have more time than money. Any advise/ thoughts would be welcomed.

Known issues:
Electrical: some gauges and lights do not work, some do. I am thinking this is where the time/cost benefit ratio will be the highest.

Brakes: currently not working. Tractor can be stoped using the foot and inch pedal and then shifted to neutral. Thinking this is not a good idea. I will try bleeding the system to see if that solves the problem .....

Welding needed to be done to rack which holds 40 gallon drum of concrete and large iron disc. Thinking 2-3 hours by a welder at around $60/hour.

hydraulic leak in power steering cylinder on the front-I have a replacement part for this. So this is free-just need to figure it out. Should I do this when hydraulic fluid and filters are replaced?

3 point hitch: missing all the tackle for this as tractor was used as a loader during its life and it came with a large counter weight and no parts. Also the PTO does not disengage when lever is shifted.

Metal: Rust is present on the tractor, but is largely superficial at this point. I own a compressor and spray guns. What is the best way to easily prep rusted metal for painting?

Fluids and filters: They all need to be replaced. Only question I have is if I can use the walmart/sams club tractor hydraulic fluid or should I buy hy-tran ultra?

Hydraulic hoses: Many of these show surface cracking, but there are no leaks and FEL loader works fine and has plenty of power-lifts front end off easily. Can I leave well enough alone or can they blow and spew hydraulic fluid?

oops meant to say hydro 84

Hi DE, the Hydro 84 is the same tractor as 784 except for drive train. It has a German D-246 Diesel engine. Re electrical, hopefully it has Delco not Lucas electrical system, there are a couple of connectors that give problems, one is under rear of seat and there is a ground lug that connects to seat platform that supplies ground to several of the circuits. Some tractors also have another connector under the battery box. Re Brakes, yes require bleeding, check archives for 674,684,784,584 brake bleeding method.
Re PTO, PTO lever linkage will be siezed up, use your favourite penetrating oil and lube everything. Under the left foot rest will be the MCV valve and hydraulic filter. The PTO actuator is under the rubber boot on top right of MCV. You may have to pry boot up and squirt penetrating oil in actuator under the boot.

3pt hitch from 584,684,784,884 should work.

Hope this helps
JimB