I think anyone who says babies should 'definately be doing xyz by x time' shouldn't be taken too seriously....unless they're talking about eating, sleeping and pooing!
If she's babbling then I'd say that's a form of baby happiness....does she open her mouth like she's trying to laugh but no laugh comes out? Caty has been doing that lately and I reakon it's a try-laugh?
Sounds like you're an awesome mum, spending lots of time with Kiara etc. so I don't think you're doing anything to cause concern