Especially with America's history of large and successful inventions spawning from garages much like in the UK coming from small garden sheds all starting from barely-working prototypes.

It's funny you've mentioned this, because I've also heard that American tourists have a reputation for not only enjoying queues like y'all in the UK, but will also form queues where one doesn't exist. I fully believe this too, because I don't think I've ever seen Americans form a mob except when we're protesting, rioting, or it's Black Friday. Otherwise, people will just automatically form lines. They'll even join lines when they have no idea what the line is for. I honestly question whether queues are even necessary in this country because we seem to just do it automatically lol.

Anyway, as for the slang terms,

I like "Mithering".

"Naff" - may be a bit difficult to adapt; something about it feels off in my mouth. It'd probably end up mangled if adopted.

"Bodge"/"Bodged" - I think this is where the term "botch-job" came from, which refers to something thrown together sloppily or carelessly in the US. As such, it'd have to buck its reputation first. Otherwise it'd probably be pretty popular as a "classy" way of saying "jerry-rigged" (basically anything from the UK tends to be viewed as being "classy" in the US, except for when it isn't; don't ask me why, I don't know lol).