@Meanlucario
Well from what I understand, Lucas wanted to do an episode or arc of episodes involving “Alien abductions” as a kind of tribute to 1950’s sci-fi invaders from space movies, and the group (which he was a part of, I believe) decided to adapt the Vong for that purpose. But yes, the plans were that they would’ve been changed so that they no longer were resistant/not affected by the force. But they still probably would’ve kept the the bio-organic weapon component as part of keeping them weird and alien.