Not exactly. One of the many grievences held by the Ameircans just before the revolution was the Transportation of Convicts to the Thirteen Colonies. If the Revolution is Avoided (my prefered scenerio), it is only realy a matter of time before Britian will be forced to halt Transportation to the American Colonies. Therefore, Australia (the best candidate) will probably still become a penal Colony, although there will probably be less free settlement than OTL, at least until Gold is discovered (a gold rush is still likely IMO) . Don't realy know about New Zealand however.
You may be right about that. I must admit that even with a North American Britain, British involvement in Australia is likely. The thing I suspect happening is less British interest in Australia, with other colonial powers (Basicly France) also trying to get a piece of it. My guess ould be a British south east Australia and a French south west and maybe a Dutch northern part (as they were pretty close). That depends on how interested they are, which wasn't much, but you never know (maybe they are used as a buffer zone between the British and French colony)
I do agree with you about the Dutch though. Although it seams another European War is inevitable, the Dutch probably won't have to suffer the humiliation and disaster they suffered in OTL's Napoleonic Wars and they will porbably end up keeping Cape Colony, Ceylon, the Malay Peninsula and the Portion of Duthc Guiana that went to Britain in OTL. However, i don't realy see the standholdership lasting for much longer and the Netherlands will probably be forced to refrom into a Constitutional Monarchy.
I will not make any predictions about Dutch internal changes. At this point in time the political situation in the Netherlands was completely unstable. Even though the patriot movement was inspired by the American revolution, I doubt that the absense (or failure) of it would butterfly it away. The time was just right for that movement. I suspect that without foreign involvement the stadholders will lose and the Netherlands turns into a full republic, maybe not that unlike of the OTL USA. But foreign powers will get involved. The stadholder had the support of the Prussians (through mariage) and probably the British, which was reason enough for the French to support the patriots. I have no idea how that would end. I suspect that they will force the Netherlands into the status quo (foreign powers love the status quo in other countries), although the stadholder would prefer to become kings (constitutional or not), while the patriots want to completely id themselves of him.
The problem, however, is that the Dutch are already on their way out. They didnt' have the navy to defend the Cape Colony, the Stadholder is so unpopular that Prussian troops had to restore him in the 1780s, etc.
I am not certain what you mean. If you mean that the Netherlands was in decline and losing the power it had during the 17th century you are of course absolutely right. That is not enough reason for the Netherlands to lose any colonies. You usually nly lose colonies in a war and those wars claimed very few colonies. The Netherlands lost only 1 Indian outpost in the fourth Anglo-Dutch war for example, eventhough it completely lost that war. The British didn't even claimed Ceylon, although they occupied it. And at that point in time, the Netherlands was smart enough to avoid wars (it wasn't involved in the seven year war for example). I think that without the Napoleonic wars the Netherlands is likely to keep the cape colony (and with a couple of butterflies maybe even if there are Napoleonic wars).
If you meant that the Cape colony will declare itself independent, I am not sure that would happen. Although it is a cool idea, a Dutch variant of the American Revolution.