#2 Win conditions depending on what they are, I would say yes. Basically what you'd do is make conditions in the script requiring for the map to change or it saying you won or whatever. You can change Sandbox and make it your own by changing the splash screen and whatever else you want (except the license of course) to make it fully look like your game, it will be your game, just under the hood where no one sees it will be Sandbox powering it. I usually just use 7zip to make an .exe for it but you could use an installer as well for your project.
#3 you are free to make whatever you want with Sandbox, that is the purpose of it
If it is too kid unfriendly, don't post it in these forums though I would love to hear about it and also there has been talk about a forum for non kid friendly games.Take care and I'm excited to hear more about your game!
-mike
