Considering the your goals are to diversify into property around Brisbane. It would also seem CG is your main priority.
My thoughts would be;
- Spend time reading this forum and other peoples stories to get a better understanding of the basics.
- Sink your $400k cheques into your home loan to eliminate non-deductible debt ASAP
- Reborrow against your apartment for investments to maximise deductible debt when you want to purchase.
- Get a better understanding of negative gearing, it shouldn't be your goal. You can purchase a place for $400k renting at $500pw, this is (probably) positively geared in today environment. If you want to negatively gear this same property all you need to do is lower the rent to say $300pw, even better $100pw, now you're really negatively gearing!! woohoo! I'm not saying you need to avoid it, just don't make it your focus.
- Purchase sooner rather than later, nothing like learning by doing and you can afford to jump in with no fear. I don't know Brisbane well but buying in suburbs that have improving infrastructure within 10km of the CBD or less should yield long term CG.