Many nano fish tend to be kind of shy and skittish and often do better in larger groups ime. So, I generally would not recommend just getting 3 of these. I know it seems like a silly line, but in the case of nano fish, I always try to start with at least 4-6 unless I know that the specific fish I am looking at will be fine in a smaller number.
One of the issues with keeping fish in very small tanks is that the parameters get out of whack quickly, and a smaller water volume gives you less room for error when dealing with water changes ect. I have noticed that my errors in smaller tanks tanks tend to be catastrophic.
Personally, I would not do it for the reason aforementioned that my own personal experience has taught me. However, if you want fish, I would instead suggest you look into the least killifish or possibly the pygmy sunfish or scarlet badi. Maybe a single dwarf puffer (mmmmaaaayyyyybbbbeeee). These are all fish that do alright in smaller spaces, and do not need as big of a group for their well-being.
Some people would probably be fine with putting the green neons in your tank though. It depends on what you, personally are comfortable with. They tend to be a shy fish, and generally swim horizontally in the upper parts of the tank.
Two roads diverged in a yellow wood, but thankfully they both led to fish stores.