Do not forget that most of the world's smartphones are being built (and built rather well) in China.

Made in China is not the same as designed in China. The companies having their designs manufactured in China just need to monitor quality continuously because Chinese manufacturers are capitalistic and will do unscrupulous things to increase their profit margins.

I personally corresponded with the CEO of a US company that got bit so bad on one product that they decided to buy back stock and discontinue it. I got one that slipped through and ended up at a surplus store.

 

how could I have known which type of power supply is expected here?

It is in the instructions but it's easily missed if you're not aware of the significance. You can also trace it on the circuit diagram.

I assumed it would make no difference to the circuit, except possibly making it more difficult to replace the IC if needed? (boy do I regret that now)

With just a soldering iron it will be a major pain to get that IC out in one piece. I would assume the IC is toast and clip each lead close to the body, far from the PCB. Then remove the leads one at a time. If the solder is still coldish you might strip some pads pulling the leads out so be aware of that. Adding a little bit more solder can help removing the leads when the solder already present wont melt. After that a solder sucker or solder wick is probably needed to clean the holes.