When we talk about all the components involved , all the different size particles etc would they all travel out at the speed of light. How far do they go? Do some run out of energy ?[i
Light and all electromagnetic radiation travels at the speed of light. That's effectively by definition. Radiation does lose energy - when the CMB first started it was very energetic, and over time that's been lost from interactions with matter and other light particles, and the vacuum itself. But when light loses energy it doesn't slow down - it changes frequency. The CMB that is now microwaves used to be X-rays, or light, or gamma rays (I'm not sure which, actually, but probably a mixture). As time passes and they lose energy the light turned into microwave radiation.
[i]Now we know that all the cosmic particles in that image are travelling at the same speed away from the source , so how can they still be there 14 billion light years later.]
It was emitted all over the Universe, and because spacetime is curved that means that the light is trapped and can go round and round in circles. There's not going to be a time when we stop seeing this, at least not for a very long time. The CMB isn't a "blink and you missed it" phenomenon, because of the fact that it was emitted all over space itself in all directions.
[i]interstellar space is not a complete vacuum//
At that point in time there woudn't be any interstellar space. [i]
True in the strictest sense, but the space is still there independent of the stars. There is no such thing as a perfect vacuum, just to the complicated laws of Quantum Field Theory. There is always stuff there, popping in and out of existence, and even more happened if you have curved space on top of that.