1. A iPhone charger would defiantly work however the voltage/amplitude may not be perfect for the battery, might start to lose charge easier but I am not an expert. I'd say get an adapter with the proper voltage/amps.
2. I would format it but you don't need any special software, it's not like Panasonic does anything special that Window's in-built formater can't. Just make sure the format of the card isn't NTFS, you are safe with FAT32 but you can't stick files larger than 4GB on there just as a reminder. exFAT works fine too.
3. The thing should come with a fair amount of charge on it due to in-factory testing etc so it shouldn't that that long to get to 100%. Takes a few hours from 0% to 100% (about 3, as eragon has said.) but you shouldn't really let it die completely, though can't say I have counted the minutes during a charging cycle.