KS1.3 should autoload the driver from the st506 controller card. it should also recognize the memory on the main board of the pal jr. as fast mem. Good luck with that mfm hard drive. Most that ive tested have failed.
any a2000 board that can physically fit should work.
You should get ks1.3 floppy and wb1.3 to continue.
actually try to find them in your collection that cam with the paloJr
good luck