Slick - $.02 -
1. Apply. You don't exist if you don't apply.
2. Yes. 121 experience is valued. Other flying might be less valued.
3. No limit.
4. Realistically? Probably not but maybe. They don't tell us what the answer is.
The median guy, often with a lot of 121 time, is in the 5,000 to 7,500 TT range and 3,000 to 4,000 hrs PIC. You're about five years from that.
You don't want to get 'stuck' at a regional? If your current job is worth getting stuck at why apply to the majors?
DAB '09 grad? Are you 30 yrs old? The average new hire is about 36 yrs old. You're low on experience and age. Work to make yourself better in the years ahead so that at 32, 34, 36, 38, etc, etc you become more and more competitive.