Systematic atomic structure calculations of KLL Auger electron spectra froM ''hollow'' atom configurations 1s2l(2)3lZ-3 are performed for atomic numbers 6 less-than-or-equal-to Z less-than-or-equal-to 10. In comparison with the corresponding 1a2l2 Li-like configurations it is shown that the additional Z - 3 M electrons, apart from taking part in LLM Coster-Kronig transitions, can be regarded basically as mere spectator electrons, neither severely influencing the peak structure due to the Li-like core nor affecting the KLL Auger transition rates. However, due to screening effects the spectra are shifted to higher energies by an amount scaling with square-root Z - 3 when adding the Z - 3 M electrons. The results facilitate the identification of distinct narrow peaks in projectile K Auger spectra observed in slow highly charged ion-surface interactions. It is shown that especially competing LLM Coster-Kronig transitions have to be considered in order to account for the measured relative peak intensities. A cascade model of the last deexcitation steps of a highly charged ion in front of the surface based on the atomic structure data provides detailed insight into the time scales involved.