Is there a legal way for a company to make iOS apps on Windows?
My advice is to try as hard as possible to get an Mac.
But just to provide another alternative :
Try Phonegap. It's basically a HTML5 wrapper, mainly used by app that needs to be published in multiple type of devices. However it also able to access native resource like camera and storage, which you can see in their feature page.
If your concern is more into development machine, by using Phonegap you can develop an app in any OS. You don't need to buy multiple mac for all the developer.
PhoneGap also have a service called PhoneGap build which is actually a cloud service that able to build your code to multiple platforms, including Iphone. This is legal and you can publish it App store.
If one of those ways is running OS X under a Virtual Machine... Is
it possible to do it with OS X Lion USB Thumb Drive?
No, You can only run OSX virtual Machine in OSX also.
Creating games on OS X (VM) would be hard?
It depends on the developer. But since the game should be tested in emulator, your question is not that relevant.
In the case we get the Mac (mini)... Would we need the Magic Touch or Magic Trackpad to test multi-touch? Or is only possible doing it by pressing one of the keys plus the left click?
Xcode Emulator able to simulate that. Read this blog
Creating Web Apps would be a solution? I know that we can't use the
Camera of the device using Javascript but is the rest ok?
If you are using PhoneGap, it's basically web apps wrapped by native. It's still give you access to resource like Camera, Compass, Storage etc.
