The 100 hourly costs for a Rotax powered Sling or Foxbat for example will be significantly less than you've quoted for the Warrior and the engine would be closer to $26k and you'd get around $6k for your used one. 100 hourlies would be closer to $1,000-$1,500 (especially if a new aircraft) but... the hire rates are less. 3.5-4 seats in a Warrior but they will rarely be filled in a training environment.
Your insurance estimate is a tad low too and the parking fee may be a tad low too although I'm a little out of touch with Moorabbin parking prices. If you leave it parked outside, you're going to need a paint job after 8-12 years? perhaps and that will cost $15-30k? but some would say cheaper than a hangar, but flying school aircraft aren't usually hangared, is too expensive and annoying to open the doors and drag out so it's left sitting in the high-sun all day anyway.
Perhaps go and visit one of the maintenance shops that service the Foxbats and Slings at YMMB and ask them how much for a service. If you can't find one, try Westernport aircraft maintenance at Tyabb as I know they do Foxbats and Bristells for Soar occasionally. Rotaxes should have 25 hourly oil changes if running on Avgas. I'm not sure what fuel Soar et al use.
You haven't mentioned what YOU want out of the aircraft other than as a business concern.
- How fast do you want to go?
- Where do you want to fly to?
- What type of runways will you be landing on?
- What fuel do they have there?
- How many passengers will you carry?
- Do you want to fly at night, on instruments or do any aerobatics?
Raaus versus GA? Moorabbin is full of sausage factories with no decent social atmosphere except maybe at Royal Vic Aero Club. You'll get the exact same social experience at Moorabbin regardless of your aircraft type or registration.
At the smaller airfields out of town, there are healthy social clubs of both raaus and GA so I wouldn't let that be a deciding factor.
Someone posted on here a few months back saying that they get $80 an hour for their older but in good nick 182 and he's paying for everything (except fuel of course).