Thanks for the responses so far, it all makes sense. As Murdoch correctly states, having the answers to my own questions would help :)
I have to admit I'm having trouble figuring our what to expect regarding returns. I have some investments now (~100k in a few individual stocks, an ETF and a few LIC's). I don't really plan on disposing of these in the immediate future. I will be investing considerably more, most likely into a combination of Aus\US\International ETF's. Haven't figured this part out exactly yet either.
I know a trust has many other useful functions, but for me, well I should say us, being my wife and (young) children, the main purpose is about tax effective distribution of the income. A secondary reason would be asset protection. Neither of us run our own business, but I suppose there is always the chance of litigation in our fields. The work arrangements for us both are a bit fluid right now, though I can see at least one of us "gainfully" employed for at least a few more years.
The whole FIRE discussion in our family is very new, and there is a lot to digest. The points around getting assets in\out of the trust seem very relevant - i.e. I don't want to neccessarily go and invest everything in our names individually at this point and then shortly after figure out a trust was the way to go. On the other hand, if we get to the point where passive income is enough to sustain us, then the costs of the trust will seem a bit excessive.
Much head scratching to do, and money burning a hole in our pockets :)