Yes, actually. And Cerberus appearing in the game constitutes an appearance. Finally, what's the purpose of the underlined?
They wouldn't even have to appear. It was an event from ME3. The Ark project is concurrent with ME3 in this idea. Get over it.
Word choice. We've already seen the token admiral. How about something else, token though it may be?
So pick the next highest rank or make one up. Stop getting bogged down in irrelevant details.
I don't want one appearing in a major way. One being implied (and maybe dealt with later) is fine.
What's the difference? Now or later, what does it matter? If they're not Reapers then what is the problem? If the Andromeda galaxy doesn't get reaped every 50,000 years then there could easily be a race or races that are millions of years old.