As others have said the stabilizer is a necessary step to stop fungal/bacterial attacks on the film. This may only occur after many years, but could ruin your negatives in the long run. Stabilizer is also said to stabilize the dyes in the film, although this is no longer necessary as C41 the film has had stabilizer built in for the last decade or so. There is an interesting post here about it http://www.apug.org/forums/forum40/1...tabilzers.html. Stabilizer is not necessary for B&W as the silver has natural anti-bacterial/fungal properties.
Bleach bypass is not a technique i've played with myself, but my understanding is that it is often just reduced time spent in the bleach rather than totally skipping the step altogether. As you say this would end up with very dense negatives.
As far as the temp of the blix stage goes, I imagine there is plenty of scope in the temperature you use, but if you are heating up the developer, why not do the blix at the same time. Blix times extend considerably as you reuse it and having it at higher temperatures may help to keep the times within reason.