My initial investigation would make me comfortable going Richards Bay, Madagascar, Seychelles, Maldives, Cocos, Christmas Island, over the top of Australia down into Brisbane. I would be interested in hearing from anyone who has done the trip before either way from SA to Australia.
I don't know if this constitutes a thread hijack - I'm sure we'll be told if it is.
I did the trip you're contemplating in 2004. I can give you some advice but no responsibility if it doesn't work out - it's a tight weather window.
Firstly, you have a few too many stops that are kind of out of line. If you're going to Seychelles you won't want to go all the way north to Maldives unless of course you specifically want to visit Maldives. But if you do, the weather window is a problem. Why? Because the best time to cross from Seychelles heading east is in March/early April and the cyclone season in that area is from December to March. In April the SE monsoon comes in and you'll be beating into 25 knots for 4000 miles. At the same time the counter current at the equator stops and you sail into a current from about 170 degrees E. So your timing has to be spot-on and not negotiable.
You also won't want to visit Christmas Island and
Cocos because that's just a dog-leg that has no merit. My choice was Christmas Island but that was because I was doing a "delivery". I believe Cocos is MUCH prettier but you choose. I just don't think going north to Xmas after Cocos is a great idea, Xmas is not good enough to justify the effort.
All that said, leave Richards Bay in early Feb with a careful eye on the low pressure cells around Chagos and stay close to the African coast as long as you can. That way you minimise the chance of sailing into "nasties".
Stay in touch on the SSB with Fred in Durban, he's great with weather and other help. Get his schedule on-line or from Cruising Connection in Dbn.
Stop in Nose Be for a week (look after your stuff, the local "boat boys" will steal you blind). If you get a cyclone coming at you on the way up the Mozambique channel, go to Ilse de Mocambique for refuge but make sure you have a coastal pilot. Try and cross the channel (read current) on a west/east course, if you don't you'll be going south
Leave Seychelles/Maldives no later than the 1st week in April. If you dally, you'll pay for it in blood. The sea, wind and current will turn against you and you'll have a nightmare trip.
If you want to stop in Darwin (logical choice) get good at anchoring and have a very good tender. Why? Darwin has a tidal range that can get as big a 14 metres!! You will anchor 250 metres off the yacht club in 15 metres deep and you will be bumping on the bottom at low tide. It's lotsa fun.
Believe me, this is not a fun trip. You'll have all the real cruising boats passing you going the other way. It's a crappy ocean and you're rubbing it up the wrong way. If this is a cruise (not really necessary) rather try either going east to west around or seriously consider 37 degrees S. The trip your planning is not a cruise, it's a struggle from the moment you leave SA.