Finding Specific Airport Delta Counter Info

I’m managing a group tour this summer and the tour company is booking through Delta group travel. First flight at 6 a.m. - 1.5 hour bus trip to MCI. Tour company suggests 3 a.m. arrival to MCI.

What are the chances that the group check-in counter is open at 3 a.m.? When I’ve had early flights before, arriving early was futile because the counters were still closed.

I can’t find a direct Delta @ MCI phone number, and so far contacting Delta gets a “sorry, I don’t have that information.”

I don’t want to put 50 people on a bus at 1:30 a.m. for an hour and a half only to sit at the airport for an hour or more waiting for the check in counter to open. Anyone know what time they open at MCI or know who I can call?