I know this is a necro …
For each “State Machine” create a Cache Pose. Then use “Blend Pose by Int”. Hook each State Machine Cache pose into the Blend. Create an Integer var and plug it into the “active child index”. Create a new Cache Pose for the output of the blend. Use this new cache pose as the locomotion down the line.
In the Anim BP event graph create the logic to “Set” and “Change” what state the character should be in. This should be plugged in to “Event Blueprint Update Animation”.