I was wondering if there's a way to change the notification icon from the @ with the mail logo to presumably just the @ symbol (similar to how it is when the app is handling network services)
Sorry, no, the notification icon is derived from the app's icon.
It's intentionally different from the "ongoing sync" icon, to avoid confusion ("did I get new mail or is the app just checking mail now").
And I also wanted to know if there's a way to have the Accounts Panel show a list of the accounts instead of the circles,
Available in the recent -dev versions here on the forum under "development builds" or in Google Play here:
https://play.google.com/apps/testing/org.kman.AquaMailYou will need to enable (turn on) app settings -> look and feel -> "with account names" (just below "accounts panel")
is there a way to remove the badge count from the Accounts Panel list
There isn't -- but it's funny, I kind of think of it as a feature...
Perhaps you've got many many many old old old unread messages?
Do you have anything to lose by marking them read ("good email hygiene"

)?
You can do this in AquaMail from its main screen, by long pressing a folder at a time and choosing "mark all read".