The conflict is simple: quantum fields are conservative, which means you can't arrange mass/energy in one way, and then rearrange it another way, and end up with more energy than you started. Gravity is conservative: if you drop a ball, friction aside, it will bounce back into your hand. It can't go higher, and there's no magic you can do by arranging matter to come up with a path where it ends up with more energy than it started with (unless you steal the energy from elsewhere).

Any such effect that exists, would not be called the "Casimir effect" because it would have to obey completely different laws than the actual observed Casimir effect seems to. The Casimir effect is actually evidence against such an effect, insofar as it's perfectly explainable in terms of conservative forces.

I see no word "Ether" in your post. LIGO (which is basically Michelson–Morley experiment at much higher scale and precision) already demonstrated waves in Ether/QF(Quantum Field)/PV(Physical Vacuum)/Space caused by merges of black holes, so I see no point to play this word game anymore.

I'm unsure about why you think that laws of conservation will not hold for Ether, AKA Quantum Field, AKA physical vacuum. If we will be able to get energy from QF, QF will lost that energy and will cool down, so Casimir effect will be smaller until it will vanish. However, there is no shortage of PV in space, and Sun is pretty good at heating it.

However, because of wave-particle duality, and because waves are propagating without moving, and because waves are propagating at speed of light, Casimir effect may be unaffected by rotation even when exposed to raw vacuum for speed less than 50% of speed of light.