Those are question you need to answer yourself. Don't expect the opposite party to do the research you need to bring up as an argument. This only proves you don't have a counter to come up with. I could simply stop here and end the debated in my favour. You only asked questions and didn't offer any counters, but since I'm so nice, I will give you those answers. This will be my last time debating for you, instead of against you in this debate. You can thank me later.
For your answer, the photon that wasn't absorbed goes nowhere. It just gets destroyed, when absorbed, and its energy transferred to the absorbing matter.
Unlike matter, all sorts of things can make or destroy photons.
The movement of electrons is responsible for both the creation and destruction of the photons, and that’s the case for a lot of light production and absorption. An electron moving in a strong magnetic field will generate photons just from its acceleration.
Similarly, when a photon of the right wavelength strikes an atom, it disappears and imparts all its energy to kicking the electron into a new energy level. A new photon is created and emitted when the electron falls back into its original position. The absorption and emission are responsible for the unique spectrum of light each type of atom or molecule has, which is a major way chemists, physicists, and astronomers identify chemical substances.
In a nutshell, the cycle repeats endlessly giving the illusion that light is eternal. It is not.
Barragan can age kido which is spiritual light. And yes, spiritual light is the same Kizaru's light per verse equivalation, but even if it wasn't, real light in Bleach was created from spiritual energy that existed first making it the natural light of the verse in the first place. I rest my case.