note: I am the resident clown, so please wait for a professional to answer your questions.
You would think so, but whatever glitch is happening seems to require direct atomic scale knowledge. The quantum eraser experiment (as well as this one: https://www.physicsforums.com/threads/double-slit-detectors-question.890825/#post-5604049 ) proves its not the detectors effecting the outcome.
I assume that they don't collapse ..they just continue being in a energy wave state until they hit something
Entangled particles are thought to be of the same particle ..well, a complex two-particle system with an indeterminate state
QM is the study of what we are allowed to know