Is it realistic to collect of investment that they are planning - 7.5m $ in equivalent?
Yes. The project probably will get this money because of growing number of users. You have written about their number before, by the way.
Of course, it is realistic. But you should always stay vigilant, keep an eye out for fluctuations, respond fast and well who knows, you might earn a buck.
This is if we talk about each participant separately. The project itself is just successful, I'm sure it can achieve its targets.