AddPlayerPacket adds a player to the client it's sent to when all the fields are filled properly. It doesn't do anything with armour
Why do you want to set armor to a FloatingTextParticle ripoff? It won't be visible, and even if it did, the entity size is decreased by a factor of 100. 99%100% accurate statistics of the players won't notice that tiny steve skin player.
Can you draw a rough sketch of what you are thinking? Mob*EquipmentPacket would have answered your question but then the 0.01 scale is a problem.