Are photons absorbed by expanding space? Can a photon/EM-field-excitation redshifted by spatial expansion be completely dissipated? Does the energy reach a minimum value (Planck's constant) and continue on as normal? Does expansion also cause energy to be lost from travelling massive particles, as they too have a "wavy" aspect? From an informational point of view, where does the info go?
 A: No, EM radiation cannot be completely dissipated. It simply expands to fill the increasing size of the universe, so that each cubic meter contains less of its original free EM energy as the universe grows larger. That reduction is reflected by a decrease both in the frequency of the light within that volume and by an overall dimming of the light.
There is no minimum frequency or intensity of EM radiation due to Planck's constant. All Planck's constant does is decrease the likelihood of finding a photon of EM energy in any one volume of space. That's not the same as disappearing, since until you look for it, the EM photon is just as likely to be in one such volume of space as another. Planck's constant only quantizes the detection of photons, not the existence (or minimum level) of the EM field itself. It's one of the odder features of quantum mechanics, that.
Particles also become less likely to find, both classically and (if you choose) if viewed as quantum particles (field excitations). However, in the case of particles that have mass and thus location in space, taking a simple classical scattering the particles over an increasingly huge expanse of space will give you about the same answer as the quantum approach, but with a lot less complexity. (There are some exceptions to that, e.g. certain types of molecules are far more likely to form in cold space due to quantum tunneling.)
