Kickstart/WB 1.2 on a stock A500? Getting ADFs to it will be tough, unless you are willing to make an inverstment.
1) Buy a Catweasel MK3 (out of production) for the PC, or wait for Catweasel MK4. With this card you can create Amiga disks on a regular PC.
2)Buy extra memory, extra external floppy drive, crossover cable and CrossDOS for the A500. Then you could very slowly transfer one ADF at a time over nullmodem and unpack it to a real floppy disk.
That is the 2 main ways. There are other unusual ways, but they are quite geekish and not easy.