Assuming the season is cancelled...
I think we'll see draconian measures from the NCAA so that roosters don't exceed 85.
Seniors: if you're considered a SR in 2020 then you're not eligible to return unless injured. This means that King, Williams, Harley, Roche, Ford, McCloud, Carter, Borregales must leave, with Rousseau and Jordan joining them as early draft entrants.
Juniors: no redshirts for anyone entering their 3rd year of school. If you're a JR in 2020 you automatically become a SR in 2021.
Sophomores: If you're entering year 2 of school and have not used a redshirt then 2020 is your RS year.
Freshmans: all incoming FR get a redshirt
That said, here's a scenario where we'd have 19 senior starters against Bama.
QB Perry SR
RB Harris SR
WR Few SR
WR Pope SR
WR Wiggins SR
TE Mallory SR
LT Herbert SR
LG Donaldson SR
C Gaynor SR
RG Scaife SR
RT Hillery SR
DE Phillips SR
DT Silvera SR
DT Miller JR
DE Harvey SO
LB Steed SR
LB Jennings SR
DB Frierson JR
CB Blades SR
SS Bolden SR
FS Hall SR
CB Ivey SR