I just responded in your other thread, so I will repeat some of that. The GH is soft, as 125ppm is about 7 dGH. Your pH might tned to lower, as I doubt the carbonate hardness is high with the GH wehere it is, though that can vary.
I also suggested a 20g rather than the 10g mentioned, so glad to see that is possible.
Most of the fish originally mentioned in post #1 are soft water fish. The platy is the exception, as jentrala said, requiring moderately hard water to be really at their best, so given your water I would forget any livebearers (platy, swordtail, molly, guppy, endler). And as someone said, two species of shoaling fish will be better, plus a fish (group or whatever) for the substrate.
Rasbora should be fine, but get 7-9 of them (I'm assuming the Harlequin Rasbora, see our profile here: Trigonostigma heteromorpha
Cherry barbs are fine too, again more, say 6-7. Here's their profile: Puntius titteya
Or the neons would be nice with the rasbora, a group of 8-9.
Corys, minimum 6 is fine, or you could have a couple more, you will have space.
I would recommend sand for the substrate if corys are in the tank. Play sand available from Home Depot or Lowe's or similar places is fine, I use Quikrete brand Play Sand. For plants, pygmy chain sword should work, here's the profile: Helanthium tenellum
Java Moss attached to some chunks of wood Taxiphyllum barbieri
Floating plants are very beneficial for fish and water stability. Water Sprite is good Ceratopteris cornuta
or Brazilian Pennywort Hydrocotyle leucocephala
allowed to float, or planted in the substrate and left to grow across the surface.
We should discuss the light, this is important with plants.