Is my fish tank ready?

IF your tank is finished cycling the platties. They're the hardiest of the fish you listed. Add otto's after 6 months when the tank is matured and stable. They won't survive otherwise. Neon tetra's aren't to terribly hardy anymore so add those as close to last as possible... but really I owuldn't add tetra's at all they really need a 20 gallon tank as to the barbs, oto's and rasboras the only fish you have listed that will do well in a 12 gallon tank is the platies.