Could photons generated from the many trillions of stars be some how contributing energy to dark energy? Where do they go and what becomes of them? What is dark energy and can photons contribute to it. When the total number of stars start to diminish will dark energy perhaps begin to diminish as well. What does happen to all those photons with the energy that keeps us alive???
 A: No, it cannot. See the technical definition section of the Wikipedia dark energy article.

In standard cosmology, there are three components of the universe: matter, radiation, and dark energy. Matter is anything whose energy density scales with the inverse cube of the scale factor, i.e., $\rho \propto a^{−3}$, while radiation is anything which scales to the inverse fourth power of the scale factor ($\rho \propto a^{−4}$). This can be understood intuitively: for an ordinary particle in a cube-shaped box, doubling the length of an edge of the box decreases the density (and hence energy density) by a factor of eight ($2^3$). For radiation, the decrease in energy density is greater, because an increase in spatial distance also causes a redshift.
The final component is dark energy; "dark energy" is anything that is, in its effect, an intrinsic property of space: That has a constant energy density, regardless of the dimensions of the volume under consideration ($\rho \propto a^{0}$). Thus, unlike ordinary matter, it is not diluted by the expansion of space.

Photons are radiation - their energy density goes down as the universe expands, and there is a redshift as well. They are fundamentally different from dark energy. Hence it is not possible that photons generated by stars is contributing to dark energy.
A: Photons are not dark, they are light. In a trivial way photons that do not reach our instruments are dark, but it is very improbable that the huge amount of dark energy would consist in part of a tremendous amount photons that all happen to fly in the wrong direction.
The remaining questions should be asked in separate posts.
