I'm probably not the one the stabilizer question is aimed at, but I'll tell you what I do, and have really good luck with.

On t-shirts I use the heaviest cutaway I can find, its something I get at my sewing machine store, and there isn't a name brand on it, just a store name. I'm sure its something they have packaged especially for themselves. I think it's similar to the Floriani (sp?) brand I bought at another higher end sewing store. The stuff from JoAnn's just doesn't seem to work well for me, its not as stiff as this stuff, and the designs got a little wonky. I don't like tear away on t-shirts, the design doesnt seem to look as nice for some reason, especially after washing, and the kids complained it was itchy. Though that was before I found the smooth cover iron on stuff, which I now use on everything anyway. I hoop my stabilizer and float my shirts with spray adhesive, and always use a basting stitch...a freebie on SWAK. I'm so used to floating my embroidery that today I actually hooped something for the first time in quite a while and struggled with it long enough I wish I had just floated it. On items that aren't embroidered on knit I will use tearaway, but only if its something that will show and won't be lined, like a skirt. If its going to be a lined bodice, like a Simply Sweet, I'll use lightweight cutaway. I really don't like tearaway if I can avoid it, I always seem to struggle getting it just right when its something that matters the position of the embroidery.
Now for the shirring, what I'm talking about may be just something with the bobbin on my machine...when I load that there's a channel the thread runs in, and a thread cutter that makes the entire thread disappear into the channel before putting the cover on. With the elastic thread I don't do this, I hold the needle thread in my left hand, turn the flywheel with my right until it catches the elastic bobbin thread, which I then pull to the top. My machine has a locking stop stitch, so I use that to keep everything from pulling out, I never thought about backstitching because I have this option, which essentially does the same thing, and I forgot to mention that I do it.

Sorry about that, bad tute teacher here. One tute I did read said to tie the tails together if you need to reload your bobbin again during shirring, like when working on an entirely shirred bodice, you may need to reload a few times. Tying the tails in a square knot will hopefully keep everything from coming undone. As for the Pink Fig patterns, I've only done one, I think it's called the Lydia...Teresa posted a pic of it recently. That one was easy, if you don't mind shirring, there was alot of that. The rest of the sewing was straight stitching. The sleeve measurements are way off...I think Teresa mentioned that too, so it wasnt just me!