I work for a group of GI docs, 11 to be exact.
Yes, they have taken the pills off the market. At least in KS. Potential kidney problems are to blame.
The reason to stay away from the red/purple dyes is because it lines the colon, and it makes it harder to get an accurate read. More specifically, that means cherry, strawberry, and grape, etc.
Some polyps can eventually turn into colon cancer. That's why it's always recommended to have them removed. Depending on the type of polyp found (cancerous vs non-cancerous) will determine how often you should have a repeat colon (3-5 yrs).
Tea is fine, as is soda, black coffee, even beer.
Lots of different preps are available. In our group, there are several opinions and options. Some will let you eat a light breakfast the day before, as opposed to a strict clear liquid diet. Just depends on your Dr., and your history.
The prep is definitely the worst part. We use a combo of demoral/versed. Lately, prophonyl is being used in some cases. You should be told what drugs will be administered beforehand, for allergy sakes.
You're not allowed to work or drive afterwards for the rest of the day. Those are state laws, due to the sedation. You'd be amazed at the number of people who fight this.
Hope I answered everything.
ETA - If anyone has any questions, the best place to find the answers is to call YOUR Dr's ofc directly. What works for one doesn't necessarily work for another.