I can't answer number one or two, although I understand skin cancers have also been an issue due to the high level of radiation pilots are exposed to up in the flight levels.
Yes there is somewhat of a shortage of qualified pilots at the entry level, although the carriers that offer defined career progression or better pay have no problem attracting applicants. Pay has gone up tremendously in the last few years, and should continue to go up at a more moderate rate in the time you take to finish your ratings. The stuff you have read is likely outdated, or represents sub 1500 hour jobs. You should expect to make 60k your first year at a regional, 65k your second year, and 95k your third year, at least at Endeavor pay, which will hopefully be matched by others carriers. Once you're at the majors (maybe in 5 years looking at current retirement numbers) you'll be making double what you'd make at a regional.