As others have said, need open center valves. Either combo or two valves. Since there are valves and a TC unit after you should use power beyond valves although for the low pressure involved it may not be a problem. Make sure the pressure release valve can be adjusted low enough for a cub pump. The reservoir needs to be above the TC tank since it will drain by gravity. The TC either has a pipe plug for the fill plug or has some strange thread. Easier if it standard pipe thread. If not you can either lathe a plug with the correct threads or drill and tap a hole in the center of the old plug. The size of the reservoir is dependant on the fluid displaced and some extra for splashing in the tank. The fluid displaced does not depend on the pump, valves, or hoses but only on the cylinders. For a single acting, calculate the volume of the cylinder, diameter and stroke length. For a double acting, depends on the shaft size and length, not the cylinder diameter.
The surplus center has lots of hydraulics. They will have standard mount, name brand, new valves with handles. I would look for something like that. You may also want to convert the lift cylinders to double acting, down pressure is useful at times. You may also want to get a high pressure gauge for a few dollars to set the relief valve.
From The Surplus Center: