If Eritrea and Somalia are included, surely Djibouti must be. It's less than 1,100 miles away. You've included countries that are farther away. Otherwise, good quiz.
The Bahrain-Saudi Arabian border is at Passport Island, not the bridge. The interesting thing is that it was an artificially created island set up for the purpose of serving the border.
I said this because Denmark and Sweden are connected by a bridge too and you didn't say that was a border.