Thanks so much!There are two hoses that carry coolant in/out of the throttle body, they're small, check there also hose coming out from under the intake manifold as there's a coolant tube that runs under the manifolds.
See this link and pictures
Coolant Leak Fix | Honda Odyssey Forum (odyclub.com)
Throttle body coolant hoses - which is which (photo) | Honda Odyssey Forum (odyclub.com)
You could "rent" a coolant system pressure tester that attaches to the radiator and pump some air into the system and look for leaks. You get it at any of the big three auto store then return it for a full refund. Make sure it'll fit your where your radiator cap goes.