That's a very pretty and natural looking tank, Harold.
I have five Hengel's rasboras (I think they run a bit smaller than the Harlequins) and two chocolate gouramis in a Mini-bow 7 SE Asian blackwater biotype tank. This nano biotype tank is heavily filtered and it nearly looks like a refugium with all the plants. I started with the two CGs three rasboras (Huey, Dewey, and Louie) but added two more rasboras (Daryl and his brother Daryl

) when my nitrates remained under 5 ppm with all the plants.
My rasboras were also pale from their travels from my LFS to the bag to their new home, but, like your fish, they colored up in few hours. The original three HRs schooled nicely but five is even more impressive. I don't think I'll add any more than five HRs with the larger chocolate gouramis in there but I could probably go for a total of ten HRs or so, if not for the gouramis. I'm not sure the schooling improves past a certain point, however. As you also noticed, the rasboras in the heavily stocked LFS tanks seem to break up their school a bit more than a smaller number of fish.
-Cal