Agreed. There should not be a case in which a child with an active IEP has got separate 504 plans or IHP/IHCP's, since all of those things are part and parcel of the child's care/educational environment.

If the IEP is faded, then those things that remain are rolled into a 504 plan.

An IHCP isn't about access. It's about safety and a treatment plan. Not management and certainly not about planning inclusive education.

Schrödinger's cat walks into a bar. And doesn't.