Dreamer,
I'm probably your least qualified/valuable contributor, as I neither got a cadetship nor did I end up going North to 'slog it out'.
HOWEVER, my perspective comes from one where I got to interview and medical stage with the Qantas commercial level cadetship a few years ago, and more recently to top 3 out of 130 applications (apparently) for a job up North. Although these are both monumental failures, I'm in the same race as you are.
The short answer to your question is that: if you want to be an airline pilot (via GA or Cadetship), you'll need the ME-CIR and ATPLs... if you can afford to do it while you don't have flying work, do so, because it's better than trying to take time off during flying work (IMO).
With respect to the family influence on which way you go, my comments are as follows (only having read your post, not the whole thread):
1. I just want to say that it's a shame that these days to get constructive feedback on this site for the up and comers, one has to spend 75% of the post on a disclaimer, pleading to not get hammered. It was different 5 or so years ago, and now I mostly PM my responses;
2. The ability to achieve aviation related goals whilst married with a child, is directly proportional to your partner's willingness to come along for the ride. This is no judgment on peoples partners, it's just that there are different levels of 'go with the flow';
3. Give it 6 to 18 months before deciding that having a child prevents you from doing GA work for a bit. My daughter was 5 weeks old when I headed off for my Instructor Rating, and this was while my wife still had the nurses coming over Re: the baby blues. It gets better, and it gets easier... 2 years on, my wife is prepared to head to the back of beyond for the prescribed 2-3 yrs required;
4. You aren't that old, but the cadetship is a bit like winning the lotto... you can't bank on it, and if you get it, everyone hates you. Regardless, you still have to have a more concrete plan in place if it's where you want to be.
I did a couple of years instructing, and I'd now like to use my Instrument rating and C310 endorsement to spend a couple of years learning the in's and out's of GA, and still intend to do so, but I also know what I eventually want to be doing, and being 10 years older than you are, I too am hedging my bets, and putting an entry in for a couple of the rare cadetship opportunities to become an RPT pilot.
Best of luck mate! I wish you well.
Nads.