Development worries

So Neko is a bit behind in a couple of things.  She doesn't babble consonants, like she should be doing bah bah bah, but she only makes vowel, h, and y sounds along with clicks, burbles, and growls.  Also she isn't really crawling.  She should be doing a commando crawl.  She does sometimes cover some distance but it isn't clear how it is done, more like an inchworm with a stretch and rotating action where you can't really see her moving but the next thing you know she is on you.  I wasn't too worried, because I had heard and read that all babies crawl differently and that some never crawl, but then we went to a movement class and were told that all this propping her up to sit has been stunting her development.  Ever since Neko could sit we've been propping her up and letting her play. We thought it was great since then she could play independently, but apparently she should have been on her stomach on bare floors with bare legs developing her coordination and brain function.  Doh!  With the dogs and now we have mice it isn't really an ideal situation, but Dionne the instructor said we could undue our errors in just a few days of bare floor play.  She follows a school of thought that says that babies must go through all the stages of crawling -- commando, creeping, not sure what else -- or they don't develop properly in mind or body.  They even relate crawling to reading.  So we have some catching up to do.  Neko's friend Nick who is five days younger can bah bah and dah dah and scoot and put himself into a sitting position from pre-creeping.  I hope it isn't the lack of sleep stunting her growth.