Surely if it was loose it would pour out with the water...
Not every drop is poured out.
... were those videos made in American kitchens by any chance? It's just that those living in countries without a tea drinking culture (some might say in less civilised countries
) don't always have kettles in their kitchens, and filter coffee makers/Nespresso machines just won't produce you enough hot water to brew with 
... if you have a device for boiling water, and you want boiling/boiled water, well, you're going to use it aren't you 
Sounds like a plan, I'll suggest it to the missus.
Why would you not just pour it out and clean it.Put a bit of oxyclean in it and boil,rinse and boil again.Simples.
Citric acid. Some say it on the label, some you can tell as soon as you taste it.
No reason at all. If you feel the need to kill off any common spoilage yeasts/bacteria that might be in your water, then boiling it in a kettle is as good a method as any. Personally, I wouldn't bother - I'd just dilute with tap water and take it from there. In my experience it's a theoretical rather than an actually practical risk.
As @kelper says a kettle is plenty and unless your tap water isn't safe to drink just use it.Alot get too anal and go OTT and as long as your cleaning and sanitising is up to scratch you shouldn't have any worries.
Nothing wrong with that at all, I usually make a paper funnel to spoon sugar into bottle.
A lot of people swear by that method. An alternative is to mix sugar and water, boil and add the cooled priming solution to the bottling bucket. The other is carbonation drops.
