Actually, bakers yeast is tolerant up to about 14% alcohol, while brewers yeast is only good to 5-7%. Some people are able to find champagne yeast quite cheap, which will go up to about 18%, and some turbo yeasts will go as high as 22-24% with optimum conditions, but come at a price premium. For most folks, bread yeast will give the most bang for hte buck, and is usually the easiest to find.
You should never have pressure being built up in the container. As long as you don't fill it up too full, the airline should never get blocked.
As fas as drinking it, well, if you realy want to, it probably wouldn't do much harm. It will basically be uncarbonated beer without any real flavor. As with any fermentation (beer, wine, other mash destined for distillation), the main alcohol being produced is ethyl alcohol, with some byproducts in much smaller quantities. These are the things that give you hangovers, if drunk in large enough quantities. I've toyed with the idea of using my DIY CO2 setup for making small test batches of beer instead of chancing a 5gal batch of beer that was a bad idea, but haven't gotten around to it. But, if you're that desperate for alcohol, or just like the idea of making your own, have at it.
