I would suggest you delete all the entries for avast and firefox in comodo and then allow them as they are challenged, the duplicated could possibly cause some sort of fallout.
Fortunately I know what iAVS is, it is the old name for VPS the virus signatures, had you dome as suggested try a manual update, right click the avast icon, Updating, you would then have seen the iAVS.
It is not too late to do as you suggest, uninstall both avast and comodo and reboot then install avast, reboot and then install comodo. You will of course get lots of pop-ups asking permission until it stabilizes.