Yes, both flights (MCI-SEA, MCI-SAN) have their planes seating in MCI overnight. It might not be possible to double cater as the food would have to stay refrigerated overnight inside the plane.
I am flying to MCI and back this week, I'll update the forum with my own experience about MCI catering.
Catering failure has happened to me twice in the past couple years, both times were an early morning flight ~ 6AM out of RDU (my former base) to SFO, once with UA and once with pmVX (in the middle of AS IT merger). Both time they decided to leave on time without catering instead of waiting (great decision as lots of passengers had connections). By the way, AS apologized and provided compensation without asking while UA didn't even after making a formal complaint to the 1k voice service.