How many inches are in range for each magnetometer’s detection?
How strong do the magnets need to be? Will a refrigerator magnet do the trick?
If a rare earth magnet is necessary, is it likely the magnet would cause interference with a wireless microphone system or be damaging for simultaneous laptop use?
I also plan to have glued in small metal contact triggers in use in the same area the magnet would be roving for detection. Will the required strength of the magnets pose a problem for keeping those metal triggers in place?
Are there any other proximity sensors that work at a distance of up to 2-3 feet through an acrylic/plastic container? Preferably with multiple axes of data?
It’s difficult to give you concrete answers since there are a lot of unknowns, but hopefully this helps somewhat.
How many inches are in range for each magnetometer’s detection? How strong do the magnets need to be? Will a refrigerator magnet do the trick?
This would depend entirely on how sensitive your magnetometer is and how strong the magnet you're using is. You would need to determine this experimentally.
If a rare earth magnet is necessary, is it likely the magnet would cause interference with a wireless microphone system or be damaging for simultaneous laptop use?
Magnets shouldn't have any affect on a wireless microphone system, but you will want to avoid getting magnets near a hard drive in your laptop and that can cause data loss.
I also plan to have glued in small metal contact triggers in use in the same area the magnet would be roving for detection. Will the required strength of the magnets pose a problem for keeping those metal triggers in place?
That would depend on how strong your magnet is and how strong the glue your using to hold the metal contacts down is. I would imagine you shouldn't have too much trouble, but if they come loose, just use more and stronger glue.
Are there any other proximity sensors that work at a distance of up to 2-3 feet through an acrylic/plastic container? Preferably with multiple axes of data?
Not sure about the distance, (you need to determine that experimentally) but any 3 axis magnetometer should be able to sense a magnet in multiple axes.
The magnets can be of different size and composition. Neodymium are much stronger than other ferrous. If you need better sensitivity - definitely go for this type and do some experimentation. But you have to bear in mind that magnet field strength is inversely proportional to distance cube so don’t be surprised if your sensitivity drops the order of magnitude when you double the distance.
Static magnetic field created by consumer magnets does not do any harm or interference to microphone or other computer parts - they operate at high frequency fields measured in MHz.