as a temporary measure it'd probably be fine..... but if your really looking to keep producing fry and growign them out then you need to set up a breeding/grow out tank just for this purpose. In an emergency I'd say yes put the neon's in but make sure you do really really really good cleaning, but as a possible regular solution I don't think you should.
And yes you'll love the difference in your cories if you get more of them, another thing they really love is an air pump, they play in the bubbles all teh time and it looks so much fun you want to go and join them!
according to Google 130 litres works out at just over 34gallons so I would say that you could even get a couple more than what Miss Wiggle has suggested. I have a couple of gauramis and they are beautiful fish. Maybe try a couple of those.
probably, i just made a rough guess at it so she could get an idea