They're mostly engineers or guys with doctorates ~ and they follow a practical sort of Halal avoiding pork (which your list does help them do).
Still, we've had the nearby Afghan community shoot some Iranians to death over what can only be described as religious differences.
As long as the crowd around Detroit continues to collect in like minded ethnocentric communities you will miss out on that sort of thing.
But here if you want to make sure your meat was slaughtered according to the most rigorous Halal standard you need to go visit the same farm the Orthodox Jews do where they are equipped to do slaughtering on site. Otherwise you get what you get.
It's not "my" group, nor is it in Detroit. However, the largest concentration of Muslims in the country is here and they use that website as a guide to Halal. All of them, because Halal standards are Sharia. Although each sect may take or disregard standards, that website uses the strongest.
And no, if you want your meat to the strictest Halal standard, Kosher won't cut it. Unless the Jew butchering is willing to pronounce "Bismillah al Raḥmān Al Raḥīm" over the meat.