Oh!, this a tricky one, well you can check now, of course darker color looks fine as background, light grays also, as we are using bright colors, using strong colors as background could be problematic, but if you check #138 #139 #140 i have changed the green is a litle easier to combine with different colors.
the others from #127 to #137 are the same green, blue and purple, changing a little the orange, to red or magenta.
As you can see, is always about contrast, if you preffer brighter colors as background we need to use darker colors in the logo, or using greys.
As for the dot, i preffer the orange/red.
Cheers.
Charly