Wouldn't "bitty" = small, i.e., "itty bitty"? Would I be dating myself if I mentioned Brian Holland(?)'s hit of the (early) 60s "Itsy Bitsy Teeny Weeny Yellow Polka Dot Bikini", to point out the "BITsy" spelling? The exact origin of the "biddy" spelling eludes me at this exact moment, but then I've been around a while and can be excused. If I recall correctly. What was that again? And, yes, I guess there could be some "bitsy biddies/bitties" if there could be "biggie biddies." Couldn't there?