Yes, that Adam and Eve were members of much larger, interbreeding population. In fact, 2,000 is probably too small. At least many thousands very similar transitional ape/humans.
The others were not ensouled. Only descendants of Adam and Eve were ensouled.
No. This isn't obvious to most people, but those of us working in genealogy, or biology, or similar fields are familiar with the fact that in a population, any given member in the past, in most cases, is the ancestor of everyone in the population after a while.
Let's use an example. Consider any person from a long time ago, say, Pharaoh Ramesses II. He lived around 1260 BC. He had a wife (Nefertari), and kids. Kids will have kids, and since all their descendants will be descended from Ramesses, the number will grow (you can also see this by the fact that Thomas Jefferson already has thousands of descendants after just 200 years, or the fact that there are today many millions of people descended from the few dozen passengers on the Mayflower).
So by 1000 BC Ramesses will have thousands of descendants, and simple math shows that by 800 BC his descendants will surpass the population of Egypt at the time. Of course, many of those will be double or triple descendants, but the upshot is that by then most people in Egypt then will be his descendant. Some of those people will live near the borders, or will have migrated over those centuries, so will be in neighboring countries (Assyria, Babylon, etc.) They too will have kids, and the same spread will happen, so by 600 BC a good chunk of the populations in those areas will be descended from them, and by 400 BC, most will be. The same goes for Asia Minor (Turkey), Greece and Italy by around 400 AD, and into Europe by 600 AD. Note that this happens regardless of whether or not the population is growing.
Continuing on, most of Southern Europe would be descended from Ramesses by 1000 AD (along with some of Northern Europe) and then most of Northern Europe by 1400 AD, and practically all by 1800 AD. Notice that you can do the same thing with most anyone from Ramesses time who had at least a few kids. You could also start in, say, Sweden and work south, or whatever, and still get a similar result.
So, being of mostly French and German Ancestry, I'm descended from Ramesses, as you likely are (unless you are not European, Middle Eastern or North African).
All that happened without there ever being a population bottleneck. Just like Adam and Eve, Ramesses & Nefertari were never the only ones on earth, yet, within a few millenia, everyone on earth will be descended from them. We agree that Ramesses and Nefertari, like all humans, evolved from earlier apes.
Now, imagine a population of hominids in Africa. At some point, say, a million years ago, designate two as "Adam & Eve". From a Christian standpoint, God gives these two the first souls - they are the first "full humans", even though they are very similar in most respects to everyone else at the time, and so their children can interbreed with the others. All their descendants also receive souls, and hence are also "fully human".
Now the same thing we saw with Ramesses happens, and within a few thousands years (say, by 960,000 years ago) everyone on earth is descended from them, and is fully human, and there never was a population bottleneck of just 2 people.
You many not agree with this situation described by many churches. Regardless, do you see how this works, being completely consistent in every material way with the evolutionary history accepted by science?