I have no idea about 1, but 2: I have soldered with insanely expensive tools, and with POS harbor freight specials. It's just soldering. I use a fancy-pants desoldering station, and it works exactly the same as anything else. It's just the tip you use that makes any difference. If you have a really fine tip, it'll take forever to melt the solder. If you have a really big one, it'll be harder to do fine work. But at least for a battery, you've got really big holes to work with. You'll want flux core solder, but I don't think you can easily get it any other way these days. Don't fret over it. It's literally a 3 minute job at the most.