As a Brit, I can answer some of these!
- Yes, some people still use the word ‘fella’. In a friendly “How are you doing, fella?” way.
- I have spent a lot of time in the US, and I can confirm that a lot of Americans have difficulty understanding my accent. I have a neutral accent, too, not one of the stronger regional dialect. It’s why so many Brits end up with a slight American accent as its much easier to submit than to persevere!

One part of this episode always annoys. The ‘mansion’ is located in the US. It’s pretty obvious when the Jaguar car they up in London has thin whit wall tyres, yet when it arrives at the mansion, the white walls are huge. Also, the architecture and ‘details’ of the house really are very British.

Some related trivia: The same house is used in the movie National Treasure 2!