Thanks to helpful comments, I was able to remove the variables I didn't need until cron stopped complaining.
command not found
Errors were silenced by removing the LS_COLORS line from my .env file. The fg: no job control error, as I understand it, was caused by these two lines:
LESSOPEN=| /usr/bin/lesspipe %s
LESSCLOSE=/usr/bin/lesspipe %s %s
because the shell was interpreting %s as fg.
This is unique to my case, but it got my cron jobs working with my expect scripts, so I'm satisfied with this outcome.