Has there been any signs of Quarians so far?

Was it?  I didn't know if we ever got info on which one it was and who was on it.

So you're telling me that I'm wrong because the fans would be angry at the endings and possibly choosing one as canon to continue the franchise  in the milky way. Is that not just an extension of the anger the fans had anyway about the original endings? I'm not saying the writers are blameless. They did write themselves into a corner, but the fan base overreacted so negatively that they had to change the setting.

Its not really playing devils advocate or making an assumption to say thats the reason they changed the setting. That was the reason they changed the setting. The developers have basically stated this a long time ago. 

The trilogy finished 5 years ago, does it really matter if they chose a canon ending now and learned from their mistakes for future games? I personally don't care too much about that myself because everyone played all three endings. We all need to move on. 
And if push came to shove, you could have had the next mass effect game so far into the future that eventually all three endings would merge. Mass effect are great at creating the illusion of choice in video games. For example, it didn't matter if you destroyed the collectors base or not in ME2. The IM was still using reaper tech in ME3. 

1. The reapers were destroyed but the relays were repaired. Life continues and maybe some geth that were offline (maybe the heretics) escapted the destruction of artificial life or (insert technobabble here), not all quarian ships choose to join the fleet in engaging the geth, the krogan still  had the genophage and they wouldnt be wiped out because of that. Thr genophage maintains a low population, it does not make the krogan go extinct. We don;t know anything about the hanar or drell (actually the drell were gonig to go exitnct no matter what) and some batarians didn't live in batarian space, such as the ones we see on the citadel in ME3. 

2. Shepard takes control of the reapers and they rebuild the mass relay network and the rest of the galaxy. But eventually the reapers are dismantled because they are no longer needed and the shepard AI went offline once galactic peace was reestablished. You can dress it up, I can't really go into it in a few lines on this post.
3. Artifical and organic life merge and they understand each other completely. If you put the story far enough into the future, this will happen anyway. That ending was so vague as to what the merging of artificial and organic life meant that we don't really know what that means to the ME galaxy. 

I mean don't expect me to go into massive details to address every single item of minutia in this post about how they could have continued the game after the ME3 endings. Its not impossible. 

If you go 1,000 or 2,000 years into the future anything can happen. Look whats happened in the last 2000 years of our own civilisation. Were roman philosophers writing about how one day man would walk on the moon and establish colonies on mars and fly faster then sound?

But the idea of starting the franchise in an entirely new galaxy was to escape the endings because of the fan reaction. And now thats what we got. A galaxy without quarians. A franchise possibly without quarians? If thats true, then they might as well be extinct because fans will not see them again.

The newest briefing mentions one of the Golden Worlds being Detro-Amino for Turian and Quarian colonists.

So expect to see Quarians on that planet.

1. Viability of a species is only something like 200 individuals. Even 5000 Quarians is ovekill.

2. Survivability of the Krogan isn't dependent on the Genophage, but the removal of their warlike culture. Pre-Genophage, Krogan would pop out hundreds, if not thousands of children at a time. After the Genophage, their viable birthrate is closer to human, turian, and asari. That's 1-3 children per birth. Krogan would be just fine.

And if you think the Krogan aren't there to establish long term colonies, then you have some ridiculous expectations.

1.  www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated#.VBiC_XtDLwo

2. Mordin says a shit ton of times in ME2 that the Genophage brings Krogan birthrates down to per-industrial ranges to be more in line with the other species. The vast majority of council races have birth rates more in line with humans. Pre-industrial Krogan birthrates were low because their planet is harsh and has a shit ton of natural predators that kept their population growths in check.

Krogan no longer had natural predators after being uplifted, which is why their population grew and it continued to grow because their culture hadn't adapted to their new circumstances, just like how the birth rates in the industrialized world is far lower than they were even 200 years ago when people could turn around and die of dysentery.