Well talking design in general state machines are very good at handling locomotion needs as it’s a migration pathway that can only be in one state at any given time. You can not be walking and running at the same time for example.
Looking at the migration path you have a standReloading so it’s an action state nested with in a locomotion migration path that falls with in the animation can only be in one state at any given time.
What if you want a reload while running, walking, crouching, swimming, climbing a ladder?
What if as you ask you want to switch between weapons?
This is where layering animations comes in via the use of a montage. You could add a montage slot with in the migration path after the state machine (check out the montage and slot tutorials in the video section).
You could even use another state machine if you wish.
So looking at it all from the forest for the trees perspective the question should not be how to combine action states with locomotion states but how animations could be layered so the any desirable state could be combined as the final result output.
Layered per Bone is a good option
