Particle Systems & Trail Renderers not billboarding when there's two cameras

I’m working on making a “Mirror” by having a Mirror Camera pointing to a Render Texture. Unfortunately, I can’t get Particle Effects and TrailRenderers to show up in this rendered texture when they have have a render alignment set to View.

I sort of duplicate the main object I’m trying to show in a mirror (as well as its particle effects and trail renderrs) and do some trickery to get most of it showing up properly

It seems like it billboards to the MainCamera, and not the MirrorCamera. When I turn off the MainCamera, it shows up in the MirrorCamer (even when I remove the MainCamera tag from the MainCamea and assign it to the MirrorCamera at runtime in the editor)

Is there any way to change the camera that the TrailRenderer and ParticleSystem faces?

Any help?