This is extremely accurate for somebody that hasn't lived here. I'm genuinely impressed.
The only things that I'd add are that over 50% of the ACT's population are immigrants from other parts of the country or overseas and their children, and they're present throughout Canberra's society not just in the APS. A lot of them come for uni, and there's been a concerted effort by Labour to give Canberra the image of being a 'university town' similar to the sort you see in America and the UK, like Berkley or Oxford for example.
I can't prove this, but I think it's more than fair to say that locals (i.e. Canberra Born and raised) are overrepresented in both the Raiders and Brumbies support base, but that the same can't be said for GWS or the other FIFO AFL clubs we've had in the past.
The other thing is that the vast majority of the people whom moved to Canberra when it was first founded were public servants from Melbourne, and they brought their culture with them. Pre 1940/50s they represented the majority of the population and a lot of their descendants continue to live in a sort of counterculture to this day. In other words, even within the minority local population there's an extremely strong contingent of AFL supporters.