First off - this reminds me of a TV show where there was a hidden organisation of human variant - detailed here: https://www.wikiwand.com/en/Prey_(TV_series).
There is not a lot to go on in your question - but my initial impression is that there will be little trouble based on the genetic difference - it's just not obvious enough to provoke a visceral reaction. Additionally the current 'official' social approach in the west is that discriminating on something like genetics is un-PC. Add to this the low understanding of genetics.
Your new species is smart and diligent, meaning that they are going to end up gravitating to positions of responsibility if they want them. This brings wealth, they can afford large families, etc. This seems to be just a matter of time.
We don't have a solid definition of human, and it could be reasonable to argue - with the approaching explosion of gene-based medicine - that we might find different 'species' of human. The trick would be to have your new 'species' included in the definition of human in law so that regular humans do not see them as competition.
Other more pressing problems:
Recognition - given their very low numbers, how will they find and recognise each other?
Collaboration - this is a difficult point - why do they care about their group? Humans are motivated to survive, but are by no means peaceful with respect to each other. Your new species seem to be 'artificially' cohesive as a group, how is this mediated?
Physiology - humans are a diverse bunch - how much of the population are going to be able to tell something is 'not right' with the new species? Geneticist, surgeon, nurse, dentist, barber? How 'weird' are they? How much work do they have to do to appear normal - and do they even know how different they are?
From a story point of view
What normal activities are easy/hard to do, and why?
Are the new species all decedents of a single person, or are they emerging due to some other factor - common mutation, virus incorporation into humans, pollutant, artificial meddling, etc. Remember most mutations just kill you, so the origin may be important to see where things go.
Your question indicates that there is a push to speed things up (which changes the tone of the story a bit) in which case it may be an idea to consider accelerating the process:
Gain influence/control over the gene related technologies and regulation
Consider compromising infertility treatment and reproductive medicine centres with fertilised eggs provided by the new species
Ensure that all members of the new species are well resourced - scholarships, business funding etc.
At this point you are getting into 'hiding a large conspiracy' territory, which is very difficult. It might be useful to make this 'necessary' by adding in a danger or time limit for the new species which means that they must grow quickly.