Should they be learning to hook up
basic circuits without learning Ohm's Law and the concepts of voltage,
current and resistance?


Sure, why not? Ohm's Law or not, its still a good exposure to basic
circuits.


Is Grade 6 too early to teach Ohm's Law?

My friend graduated from MIT at sixteen. I'll bet he was doing Laplace
Transform for circuit analysis and wave equations when he was at the grade 6
age.