Which races will be on the Ark?

OP, you forgot turians.
As for the question I expect only turians and salarians to be fully confirmed. As for everyone else - to oblivion. Not because I hate them, I'd like to see hanars for example, they simply never got a role to play in ME lore and proper popularity as result. So most practical solution is to get rid of them and try again with fresh andromedians, learning from past mistakes.

There was some closed presentation with new Frostbite graphics long back then. By rumors sararians were among these examples.

Yeah, the shape of the head and what was visible of the body was obviously salarian, in my opinion, so I think it is safe to say that there will be, at least, one salarian on the ARK. Whether they'll be NPC or squadmate remains to be seen. We've yet to see a shadow of a turian, though.

I'm hoping Hanar and Elcor remain present of the minor races.
Of the major ones Salarians and Quarian make it.

Can't see a case at the moment for presence of the likes of Geth/Batarians.

Salarian, volus and batarian

All! All teh races! Can't bait me…

I actually expect every sane/semi-sane race to be involved in this little venture. By bringing "everyone", we're showing the Andromedan races that we're not alienist as some *cough*noAlloption*cough* seem to be.

And cats, because while they're not space-faring, they let us "lesser" mortals do the space-faring for space tuna, which we'll come back with, if we don't want hairballs on our favorite pillow.

If it's my ark, Geth, Hanar, Drell and Elcor.

Might as well share mine. The only ones I think will be left out for certain is the bartarians due to damn near being completely wiped out and the hanar, since those ME fields might not hold up. The latter wouldn't upset me. I don't like the hanar one bit. This one finds them creepy and one-note.

Why only four options?

No ark is complete without at least 1 Sheppy the Volus

Well I know what I would do if I were part of the writing team and that is have all of them in one context or another even if they have no direct role in the story and were relegated to backdrop props. Each could be written in fairly easy one way or another. For example, you could have a few Quarian exiles who given their knowledge of prolonged living in space would make them attractive members and no home to go back to with their own kind jump at the opportunity to explore another galaxy. Geth being software could easily infiltrate one system or another and go dormant for the trip, activating and begin replicating their hardware upon arrival. You could have a Batarian stowaway (or several). I'd purposefully include a contingent of Vorcha because you need a labor force less likely to question why they're tasked with all the dangerous jobs. Hanar and Elcor in "significant" numbers are tough because of their special needs and space requirements, but in lesser numbers are doable. I'd leave myself open to options down the line since I'm sure they only have a vague idea of what any sequel might entail. More of the old provides more writing fodder to work with...so I see no real point not to include most every race to one extent or another.

What Bio and the writers will actually do, I have no clue. I expect that regardless of how many of the MW races make it to Andromeda, our interactions will be limited to the few we already know of, likely a Turian, and certainly an Andromeda race...maybe one additional.

Turhurrdurrians are a shoo in. Salarians have already shown up in marketing material.

Everyone else on the list is getting cut.