Marla will take some of the other employees with her when she leaves
Cooper and Val would probably rather work for her than stay at Grumbels and as a bonus a future strip could show their old store had been closed down, due in part to losing them as employees.
Jerry is Cooper's deadbeat dad.
There is a definite physical resemblance.
Cooper is an adult version of Calvin.
The appearance and attitude are a very good fit.
- The pedant in me points out that a LOT of people were considered for adult!Calvin at some point and I feel this WMG is selling Calvin's father short, considering Cooper's father ran from the family canonically,
The final strip
Mass resignation, then while Stuart is sputtering from it, Cooper revealing he's been married to Val the entire time just to see Stuart's head explode.- Sadly, no head exploding, and Stuart never did find out about Cooper/Val. But it was essentially a mass resignation, with only Crystal and Lunker staying. Marla recommended to Stuart that Crystal should replace her and had already advised her about what to demand to take the job.
If the strip continued
The cast would have to deal with the COVID-19 pandemic and how the general public would be putting them at risk on a daily basis through ignorance and apathy towards their health. The Obligatory Time Lord WMG
C'mon, y'all, it has to be Lunker, who finally got his TARDIS to work, and got Crystal to be his first companion. (If this had happened a few years earlier it might have been Cooper, but I feel Lunker respects that he wouldn't leave Val.) If Dollar Admiral ever gets turned into an actual comic strip, characters from this comic will show up from time to time
Hopefully someone who was glossed over in the final Story Arc (i.e. anyone not named Cooper, Val, or Marla) like Lunker or Crystal. At least that way they can get some closure.