You can charge the battery for 24 hours if you want or when the light turns green.& make sure the camera body is a local set with 12 mths warranty plus additional 3 mths online which makes it total 15 mths warranty.
nobody knows, because different brand of cameras had different warranty coverage. As long as it is a local set, it should have 1yr coveraage and some brands give you an additional 3 mths or more. You can also opt to get extended warranty which sometime amount to 2yrs for some brands of cameras.
First time charging will go till the battery is full. Charging times depend on a lot of factors, there is no generic answer. Most batteries come preloaded anyway.
Warranty coverage depends on where you buy. Official shops will give the standard warranty (check the warranty card, ask the shopkeeper), grey imports come with shop warranty. Do read the sticky thread for more details.
Anything else - Read the sticky thread, we have them for a purpose.
For me, i will charge 6-8 hours for the first charge then subsequent charge, i will turn off when its full. Most electronic goods are 1 year warranty (additional 3 months when you register online at Canon website) unless stated otherwise.
Lithium battery comes precharged because low charge on Lithium battery is damaging to the battery. They are precharged to approximately 60% as indicated in some articles so that it can withstand the discharge before it is sold. Some lithium battery are also put in "sleep" mode where only upon the first charge where it will jump out of the sleep mode permanently to ensure least discharge before first use.
I know there are a lot of vendors out there advising the the first charge of a battery to be done for extended period. I'm not an expert in battery design and usage, and I can't vouch for what I have read. But across the Internet, I have read numerous articles that modern Lithium batteries do not require extended charging for the first time.
The charger will charge up quickly got the first 80% and perform trickling charge for the remaining capacity typically. When the electronics indicate a full charge, it will not charge anymore no matter how long you placed your battery there. Lithium battery are sensitive to pressure overcharge and will explode when misused, when forced charging is never done on such battery type. The electronics will switch off when it is detected fully charged.
Calibration is done by the system and not the battery to reliability gauge the usage, hence there is information on the net advising different method of calibrating the battery typically for laptops. For camera, I haven't really read any on such. Typically after numerous charge cycles, it is normal for Lithium battery to retain up to 80% of the charges versus new, so don't be alarm if the battery doesn't store as much charge. Nothing last forever although it seems Lithium technology is advocated as such for been renewable.
Never fully empty the lithium battery, always store as fully charged as possible. This is good for Lithium. Lithium so far perform the best in cold temperatures environment, but still it will be relatively worse than in tropical climates. Last but not least, there is no need to frown over degraded batteries. They are consumables and hence just use them like one. Treat them normally and when it doesn't perform, just buy new ones.