If the AI ever does reconnect to the Milky Way...

By time Andromeda starts, she's 708. By my estimate, she'd be 808 by time that Ai was even in the position to start committing resources to building Mass Relays. And without a Relay back home they could just immediately connect to, they're more than likely going to have to build multiple ones. There'd be a primary Relay in Andromeda that they'd program out to a certain distance in Dark Space, shoot out to that point, drop a Relay, go back to Andromeda, grab another Relay, shoot out to the second Relay, program it out to a certain point, launch out into Dark Space, drop the third Relay, travel back to Andromeda, and so on and so forth until they can comfortably shoot out blind into the Milky Way to drop the final, connecting Relay, unless they somehow stumble upon the Reaper's Relay that connected to the Citadel. So by my guess, she'd be pushing 1000 at the very least.

We know Asari live for 1000 years, but that's an estimate and not a locked in number. For all we know, being 1000 is akin to being 97. One person could be fine, but that doesn't mean they're not damn near EOL.

I bet that one of the roles of the Nexus is that it would be the Mass Relay that connects Andromeda to a sibling Mass Relay in the Milky Way. That could be why we build part of the Nexus in the Milky Way so it can link to its sibling before departing. 

Well, the only way we know of. Chances are the Remnant found a way to travel across vast distances and we could implement that into connecting the two galaxies as well as expand further into Andromeda. I would prefer the former since that means Mass Relays would return in future installments even though they aren't in this game( ).

Isn't that also going to make traveling alot slower? The Mass Relays allowed the species of the milky way to travel vast distances in a very short time, compared to normal FTL travel.

I wonder how that will work out then in Andromeda.

.......Goddammit Bioware, why did you have to write yourselves into a corner!

Why would that make travel slower? We don't know how Remnant tech works. If the Remnant created anything analogous to Reaper tech, it would allow travel to occur just as fast, if not faster since Andromeda is far bigger and the "just good enough" threshold is far higher since the distances needed to travel would be greater.

Not really, having a small holo conversations with Milky Way characters is WAY lesser issue than staying in the Milky Way. You can partically "reflect" all major ME3 choices with few varied lines of dialogues.

Bioware went with a civilian lore setup for the Andromeda journey, one that actully aims to set up a link and exploit Andromeda resources. It would be ridiculous if they wrote it so that the communication was never going to be possible.

You have to forgive my lack of knowledge, I haven't really delved much into the details till a few days ago.

I admit it would be nice if that were the case.  But it's pretty clear from the ME trilogy that no one has a frakking clue how to build relays and can't even be bothered to do the research.

As themikefest has said though, it is possible for Liara to have died right at the end of ME3 and/or everyone to have died if the Refuse ending was chosen and the harvest continued.  People accuse Bioware of wanting to avoid dealing with the endings... but I think what they really want to avoid is declaring a singular canon ending.  That means that any communication to the Milky Way would have to be done in such a vague way to allow for the possibility of any of the endings to have taken place (rendering it likely "unsatisfying" for the bulk of players who are still insisting on being in the Milky Way to force Bioware to "deal with" the endings) or to "completely and finally end the ME:A saga with a return to the Milky Way" in such a manner that either, again, the state of the Milky Way and the old characters remains unknown or the player simply selects / reselects an option to declare what state the Milky Way would be in at that point.  With future improvements to gaming technology, it may be feasible for Bioware to manage a continued game that starts with such variation in the state of the setting... but I think it's highly unlikely and probably not going to be worth their while, financially, to attempt it.

Historically, part of the experience of taking the risk of migrating to a "New World" was learning to deal with the yearning to return to the "Old World" and, for many, accepting that such a return was never going to be possible.  For me, the possibility of never being able to return to the Milky Way actually makes the potential characterizations in ME:A more "real."  In addition, some of my ancestors that came to the "New World" were blatantly lied to about what they could expect to find here... so the idea that the AI might resort to lying to their participants is an intriguing story element for me.

the refuse ending never triggered a completion achievement. I doubt it us even remotely a conventional ending. Quite like sexing Little miss Ardat Yakshi Morinth.