Absolutely. There is plenty of evidence to say that federations turn a blind eye in certain circumstances. Jamaica - athletics. Operation Puerto. And if you want specific Australian examples, Stuart O'Grady and Mike Rogers. Number 3 is a real possibility.
Number 4 is entirely possible. Small town, you know when someone new shows up. And why can you not go overseas? Airfares are cheap...
Number 5 is the same. Why will that not work in Australia? It's part of the WADA code, if they can't find you, you just get a checkmark against your name - naughty boy, don't do it again.
And what about 1 and 2???
OK, we may not have to agree on everything, but the question is already answered.
Seems like you didn't like them so you're just asking the question again