1.What is the sugar water for?
Only if you have a shipment of chicks that aren't doing so well, or need a quick boost. I never used sugar water and my chicks have done just fine.
2.Do you have to give electrolytes and vitamins? If so how long and what kind?
You'll get differing opinions here, but I don't use them - basically same answer as #1 for me.
3.You start at 95 degrees for the first week then drop 5 degrees every week till when?
Until you get to 70 degrees - about 5 weeks. By 6 weeks they are pretty well feathered out and if the weather is warm you can move them out.
4.At what age can you add them to older chicks?
Once they catch up close in size they can go in with older chicks/chickens. I'd recommend keeping the 'tweenies' in their own pen but where the older chickens can see them and interact through the fence. Then once they are more of a size where they can hold their own, they can go in with the older ones. I just integrated my BOs with my older girls when the BOs were around 10 weeks and it went pretty well. Expect some sparring and picking as they work out the pecking order. It seems to be less dangerous for the little ones if you are adding several at a time, rather than one or two newbies in with the older ones.
Other tips - watch your young chicks for pasty butt. Basically you are looking to make sure their poo doesn't stick to the feathers around their vent. If their vent gets pasted up where it is blocked, that can kill the chick.
For the first few days up to a week, keep the chicks on paper towels to help them gain their footing. I put a couple inches of pine shavings down and then paper towels on top. Then after a few days I just remove the paper towels.
Good luck and enjoy your chicks!