I think the fireworks story was used to explain the red cloud. The ammonium nitrate wouldn’t.
To my eyes, the smoke of the secondary and large cloud was brown and typical of nitrogen
No, AN. Commonly has that red cloud effect as incomplete deflagration of some of the mass.
You are correct; ammonium nitrate deglagration produced ash-colored smoke. The reddish-brown smoke comes from High Melting Explosive, also called Octogen - which is rocket fuel. The four ingredients of HMX are hexamine, ammonium nitrate, nitric acid and acetic acid. All those rockets fired on Israel come from somewhere and are fueled by something. "Some things happened" to an Iranian ammunition warehouse and/or ammunition factory.