No, it’s not. The flame carries on, but only the first/nearest target actually takes any damage.
“Inverting laterally” is the same as mirroring. Do you mean “inverting vertically” (a.k.a. flipping)? In any case, all waves where this would make a significant difference already offer this. I don’t want to go edit 100+ waves just to add vertical flipping, especially since that’s significantly more disorienting.
The Yolk-Star doesn’t move (if you’re talking about the ray-guns, these still move randomly. As for the rest, it’s only fixed per-mission (so all players see the same movement on a particular mission). If you encounter it on a different mission, then the movement will also be different.
Intentional, because it means you always know which way they go during your last chance to kill them.
Waves can’t have different names depending on their placement in the mission.
Sorry – will award during the next update.