Wall of text inbound.
1. How large is the community?
Largeish. Few dozen players over the greater metro area. We've got a few down here in Mandurah but the bulk of them tend to go to TGA.
2. What clubs is infinity played at?
See above. Largely TGA.
3. Is panoceania played to death by everyone or is there a good spread?
Before the starter, there was a spread but the starter models are so damn pretty that a lot of people now have a PanO/Nomad force on the side. Honestly though, if you like the look, play em. It's not like 40k where it's MEQ versus everything else. At a fundamental level, pretty much every strategy/ability is available to every army.
4. Does the motto it's not the list it's you really ring true for infinity as I find that appealing.
Yes and no. That gets bandied around a lot but it's not as true as everyone wants it to be.
Infinity as a system is incredibly brutal and can be unforgiving. And while it's technically possible for the basic line guys in your list to drop TAGs, the odds are not in the line guy's favour. You can outplay an opponent but your list has to factor in. So, short answer, it's not true. You need to learn to take a variety of choices when you make a list and learn to play those choices well.
Having said that, a knowledgeable player with a sub-par list will beat out someone who doesn't have an understanding of squad level tactics but has a killer list. The balance of power shifts to the active player each turn and if you position the right people in the right place, you can steamroll even the scariest models.