Re: Neon Tetra
how big is your tank?
As to your question yes guppies, swords, and neons will get along together well given you have a big enough tank to observe the rule of one inch of fish per gallon.
I have guppies, neons and shrimp in a 20 gallon planted tank (water wisteria, java moss, an unidentified moss, peacock fern, and jungle vallisneria). I have also put guppy fry in with sword fry when the two specie were about the same size (i.e. the swords wouldn't be able to eat the guppies) with no losses.