A previous analysis of the nonlinear dissipative equilibrium of a beam-penetrated plasma with nonthermal electron “tails” [D. V. Rose, J. Guillory, and J. H. Beall, Phys. Plasmas 9, 1000 (2002)] is extended to the case of a relativistic, momentum-angle-scattered electron beam (with or without accompanying ions) penetrating a fully ionized low-density nearly collisionless plasma, and to include the energy balance of the nonthermal plasma tail electron population on electron collisional timescales long compared with the primary instability growth time. Quasistationary nonlinear “dissipative equilibrium” states are quantified for various ranges of relativistic beam parameters and various tail-enhanced Landau damping rates for shorter-wavelength space-charge waves. Conditions for quasisteady wave populations are found, and for energy balance between beam energy input to and dynamic friction cooling of the nonthermal “tail electrons.” Finally, some potentially incorrect inferences based on a thermal interpretation of bremsstrahlung from such a plasma are quantified. All of these microphysical processes evolve on timescales inaccessible to conventional magnetohydrodynamic modeling of astrophysical jets, and may lead to energetics corrections to such fluid models.