Is there anything like a link or shared mount point for FAT32 folders in Linux/Android?

It is possible to mount a folder in another folder if you have root.

open adb or terminal (adb is preferred) and type

mount -o bind /origdir /newdir

This should have the same affect as ln and will work on FAT32 filesystem

Endolith answer is best for your situation, but Sathya is wrong, there is also solution, if you really need to fake link(hardlink), see: https://stackoverflow.com/questions/4545536/faking-symbolic-links-on-a-fat32-formatted-storage Though i hadnt tried it on android.

FAT doesn't support symlinks.

Is there a way to make two different folder paths on a FAT SD card point to the same file

No.

Can FAT be extended to support them

No.