Could this open the door for seniors-to-be getting a free 5th year? I.e. Could athletes that have played each of their first 4 years -- like Lyght -- theoretically come back for a 5th year?

If an athlete didn't redshirt at any point during their career, they can choose the new rules which would give them a 5th year of eligibility.

is that the 5 for 5 is retroactive to include players who had just used 4 years of sports eligibility in 4 years. It is no-go for any of those "potentials" who have signed a pro contract in the meantime. So most of the Syracuse lacrosse players are Out.