L285P power steering instal

Sorry this will not be the answers that you're looking for, but they are honest answers.

Well you can't make it close to factory, as they never made that model with power steering, or any other model close enough to just bolt parts on.

Being that it never came with power steering will make it quite difficult as trying to find a gear box to swap is about impossible, then finding the proper valve to run the hydraulics (priority valve) will also be very hard.

Even trying to do any kind of add on will be very pricey, most aftermarket solutions that you can easily come up with will run you in the $2k range.

One solution would be to change it to hydrostatic (full hydraulic) steering, but that too is not cheap or easy to do.

Now for the next part of you request, Putting a loader on a 2WD Kubota is highly inadvisable, number one because they are very hard to handle, and the 2wd front ends were on the weak side to be using a loader with them, you could very easily end up regretting putting a loader on it.
Trying to find parts for the front end of that rare model might leave you without any tractor at all.

The on board pump would work for the hydraulic for a loader but yes it will be slow.
Adding a front pump to that model is not easy again because the rarity of the front pump hub, couplings and drive shaft.

A honest, and a "been there done that suggestion" would be sell that tractor, and then buy a newer loader equipped 4wd Kubota.