ketosis is nice, but no, it does not automatically mean you are losing fat. you must also insure that you are below BMR (the 10x rule is simple and effective) because if not, then your body will spend its time metabolizing your incoming food and you won't burn fat. its a balance: go too low in cals and you invoke "starvation" (catabolism). too many cals and you still put on weight (albeit slower than a regular diet, but counter-productive nonetheless). as for me, i keep my caloric intake at 10x but when i don't exercise, i go as low as 7x.
creatine is mostly ineffective during ketosis since insulin isn't doing much work during this time, best thing to do is take advantage of carb-up and insert as much creatine as you would for loading into your meals (but avoid excess as some folks get the caca attack), because it is during carb-up that your insulin kicks in again, your body is primed for carbs, and you basically slingshot all kinds of good things into your muscles (stay away from fat while on carb up as much as possible, as you slingshot this stuff into your body very efficiently too during carb-up)
as for how long...... everybody has an opinion, but keep in mind CKD proves useful to most athletes for the way you can diet and avoid catabolism much longer than almost any diet, and the best way you do that is keep your ketosis days under 10 and your carbup period under 36 hours. A simple, effective, and practical solution is the one most folks use, 6 keto days, and 1 carb-up day
as for me, i keto mon-sat and sat at exactly 10:00pm, i go carb-crazy, i keep carbing up till sun at 8PM after which time i starve till morning...
it can be as simple or as complex as you want... im anal-retentive, so mine is about as complex as a space trajectory for a Mars Mission, but for the most part, keep it simple, unless you are totally sure you will follow through with your obsession ...
and it can't be overstressed ... read, research, and learn, everything you need to know has already been covered