The peons, Shibalien, Snache, and Imperator Sael, spawn at the beginning of the stage. The Shibaliens and Snaches respawn in 3 - 20 second intervals while Imperator Saels spawn in 20 - 40 second intervals. 20 seconds later, Those Guys begin to spawn in the same intervals as Shibaliens. The first Elizabeth the LVIth spawns 40 seconds in. The second Elizabeth the LVIth spawns 80 seconds in. The third and final Elizabeth spawns approx. 116 seconds in.
This stage is not as easy as the previous ones, but it is still not very hard. Since this stage is almost completely filled with Alien enemies and Shockwaves, fill your loadout with anti-Alien cats that have massive damage, freeze and slow.
Shockwave immune/blockers like Octopus Cat or Cat Machine MkIII are also very useful, while Long Distance units like Ganesha may also help wiping peons and Imperator Saels (obviously, Aphrodite shines here).