It all depends. Usually as long as you stay away from profile editing, and online game editing (ex. an offline game that uses offline character stats online) then you should be fine.
yes you can
you can do cheats on xbox live butif you get cought your xbox gets banned and no more xbox live
For any cheats or no good conduct
Xbox live will be banned but all offline features will work normally but it will have an effect your xbox 360 may crash in the middle of games it did it on me
You can download USB mods, but there are no ingame cheats. And USB mods can potentially get you banned from PSN or Xbox LIVE
no
you can go online as long as you have the most up to date firmware but you could still get banned at any time i had a flashed xbox and lasted about a year before being banned. but you can still play the home brewed games offline after
If you mean by does Xbox live ever go offline. The answer is yes, if there is work which needs to be done, it may go down for a few hours. This is not common.
you can get banned from xbox live for hacking, cheating, w/e
Yes. If you have modded your xbox, you will get your xbox banned permanently.
Hacking can get you banned from Xbox live for live
nope. once its banned its banned
around 80 bucks