Hokey Dokey. Thanks for the reminder.
I know you asked about this stocking this tank when you first got it, so you already know your stocking options are a bit limited. Have you considered any of the other mircorasbora? Like maybe erythrmicron? Or perhaps sparkling gouramis or scarlet badis? I am not positive about those last 2, but it seems to me that they would work since they are wanderers more than just horizontal swimmers.
Pygmy sunfish might be an option, but I have heard they are pretty hard to keep alive. If you want to just stick with the chilis, thats cool too.
Another option would be a pair of some other bettas species like B. simplex or rutilans? You could keep a pair of them in your tank IMO. You said you wanted more than 1 fish, but some of these other species would be fine with a pair.
Betta Species They may be a bit more than you have time for though, but there are are awesome betta species out there.