I don't know this winch at all, beyond very generic gathered information... A couple of things to ponder however-
I doubt the winch weighs what the winch cable is going to. how much is that? I dunno, but you should. The data tag will show empty and max weights. Prolly there's enough to cover all that, but it should be "known" and not "assumed"...
You have a pump "spec'ed" that does not sound unreasonable and possibly will be quite feasible, but no mention of a motor? They have to be spec'ed together. You can double the PSI and cut the volume in half, or vice versa. The ratio between the spec sheets for the pump and the motor will be the drive and driven gear ratios for the chain sprockets, and will have to accomodate the differences between the original winch drive including it's PTO drive ratio and your new application. How much horsepower is your PTO and it's mounting good to deliver? That's your limiting factor on the final speed of the winch. Too much pump or too little motor, and it drives by all torque. (Transmission parts break). Too little pump, or too much motor, and it all drives by flow, requiring huge RPMs to acquire any reasonable speed.
Of course you have twice as much (Roughly? I think) as the PTO on your truck was designed for, you can expect the design spec to have to accommodate that fact with a significant lack of speed, to the tune of about half as much as the original...?
The winch it's self... Does it have provisions robust enough to mount the hydraulic motor directly? Remember, every single inch pound that goes in will have to be reacted to somewhere, and that somewhere will be whatever you bolt the hydraulic motor to.
Watch out for used hydraulics, make darned sure that whatever you get is open center. The precision is not quite there compared to closed center, but when operating one spool at a time you'll never know the difference. They're a lot simpler when it comes to the pump, They're a lot more forgiving about less than perfect matches, pumps are cheaper, diagnostics are a lot more straight forward should it quit working (although not rocket science on a one spool system anyhow). Hold out for that.