I'm particularly interested in what types of machines and other voting procedures were in use there. It looks like they're optical scan machines, so hopefully they have the paper ballots on hand to do a proper audit. That, along with the voter rolls, should be able to determine what the issues were. That's a strength of using the optical machines as opposed to the purely electronic ones.
You're right that Detroit is just one city. It's also a city that's deeply troubled on many levels, so I'm not sure if it's fair to consider it typical. That's by no means excusing what look to be issues there. Those should definitely be looked into, and exhaustively. You're claim above is that there were enough fraudulent votes that Trump would have over 50% of the popular vote if they were removed. Detroit alone isn't enough to do this.