get a 5 gallon with a 15 watt light and do 2 small fish 3 dwarf or pygmy cories and your shrimp and live plants like java moss, micro sword , glosso, java fern and whatever plants you can find you like. dwarf hairgrass looks nice. and everything in the tank will love you more for it.
as for the fish guppies are fine but not your only option
i keep 2 serpea tetras in my 5g the reds against the greed would be beutifull. im still planing out my plants in that tank so the poor fish are kinda just shillin with nothing for cover but a shell to hide behind. i know its a sad story. ok im off track, but all im saying is your not limited to guppies although they could be an interesting choice.
honestly i dont think a 1 gallons suitable for anything except maybe a plant. some moss and a couple shrimp.