While I have never been disappointed with any kits I have used, I do like Austin Homebrew best. They seem fresher and better tasting. Just my .02. YMMV.
Not that is really matters, but I oxygenate before I add the yeast. The yeast doesn't have to be mixed as it knows what to do. I do tend to give the yeast a stir after adding, but I don't think that it is necessary.
I would give them a week or two more. Remember that 3 weeks is the minimum amout of time. There are many varibales. Knowing your SG and FG would also help as bigger beers take more time to carb/condition in the bottle. Each bottle is undergoing a mini fermention, and will vary from one another.
LOL. Yea it does make seem more like a science project with the blow off tube bubbling in a jar of water. I remember my first batch with a blow off tube. It was in winter and I had in my gettolious cardboard fish box temp control chamber in the basement. The SWMBO said that it sound like it was...