Momemtum is composed of mass (inertia) and velocity which is NOT "stored energy".
Mass in NOT inertia. Mass is matter, the substance of what we know as atoms and molecules. Inertia is the resistance to change of motion, as described by Newton's First Law.
You are right, velocity is not "stored energy", it is rate of change in displacement (location) in relation to time.
Momentem is mass times velocity, or p = mv.
Now what do you want to discuss in relation to post #359?
Mass in is NOT inertia.
Now proceed with your argument if you'd like....