/qn is entirely silent, /qb or /passive are allowed to display something onscreen.
MSIEXEC format has a set of pre-defined switches, but the devs writing the package are expected to follow the spec, and some don't. Most Office suites have some annoying post-install popup with "Click here to dismiss."
Post-Setup (Before logon) will hang, because you're not allowed to interact with the running process. Tasks are running as SYSTEM user, and therefore require security protections.