The reason most houses built today have forced hot air is because you can use the same ducts for air conditioning so it normally ends up cheaper.

There is a local group of investors that normally get together once a month.

In that situation, it seems like my gross scheduled income may not change (as a section 8 tenant vs a “normal” tenant may pay the same rent).  

Normal the price you would be approved for for a single family is not the same as the amount you would be approved for for a 4 plex, although they will probably hesitate giving you a number for a 4 plex without knowing more details about the property you are looking at.  

None of the things I'd normally do for friends and family make sense. 

Normal case, 2-3.

Comparatively, a duplex anywhere near Sydney is around $1,000,000 and rents for around $4,000 per month — no possible way to cash flow so you’d be gambling on appreciation.

The 3-5% FMV discount is normally super attractive but I'm worried that because of the incredibly high property values right now, we may be in for a correction in the next few years, wiping that discount out (at least in the short run).

If we all had 20/20 foresight, we’d just buy Apple or amazon or Microsoft or google stock with 50-100% annual returns sometimes and live our normal lives while our investments exploded in value.

Is it normal for a buyer to pay the entire cost of the Phase 1 and/or Phase 2 report?