Do you think its possible for an indoor cat, lets say..... over 2 years of age, to become an outdoor cat?

If it is in their personality, yes. If the kitten was born outside like my Lilly Anne was, then I guess it is even more possible.

Couldn't say for any but mine, and these spoiled sweet hearts would make it for maybe a few days then they would be trying like he## to get back in. ;)