Glad you liked it. Thought the different perspective would be cool.
The there are two benefits I can think of immediately to running hydraulics. First, the two boom cylinders are run in parallel with each other as are the bucket cylinders. This means they will always be "phased" with each other and should always share load equally. With linear actuators, you have to make sure they are correctly phased, otherwise they can fight each other, twist your frame, etc. Second, if you stall the loader (max it out, or run it against the stops) in a hydraulic system, the relief valve will crack open and bleed the excess fluid to maintain the pressure at a safe level. This is something you'd have to work out with the actuators.
This loader's bucket is getting pretty thin from being neglected for many, many years. It has many pinholes, and accordingly I'm going to be having a replacement rolled. When I get some quotes, I can give you a feel for what you're in for. The rest of the loader could probably be made out of box beam. If you're going to go that route, I'd recommend biting the bullet and buying a horizontal cutoff bandsaw that can be used vertically also. It will save you lots of aggravation.
My loader's running a replacement hydraulic pump that I bought from Surplus Center, I can share that info with you. Valves are available from Surplus Center, Bailey Hydraulics (baileynet.com), and many other sources. The original valve is a Wardco valve, which was also used on Wheel Horse tractors, and is available on eBay. Also, o-ring kits are available direct from TORO.