You are right about the salary starting at $101,075 for a Level 1 FO. But I don't know were you are getting that they are required to be hired as a flexi line pilot?
I think you will find that they will be full time pilots. So they then have the option of highline that gives you an additional payment per duty hour worked as well as duty time allowance. Average duty per year is 1120 hours per year.
These new pilots will not start until after July 2016 so they would be looking at
Base $104,107 plus $5.79 per hour of duty. Average duty hours per year equals another $6484 plus DTA of approximately $5756. Total salary excluding extra flying allowance or day off payments equals $116,347.