Open question. Vast majority will do nothing. Possiblt 'cause there is not a lot they can do. Some will squawk. A very few will park up their mining vessel and try and bump you 'til you get bored and warp off.
In majority of cases, there will be no-one else actually mining who is a member of the owner-corporation anyway. (This is probably time zone dependent). If there is, you can, 1) ask if ok to mine, 2) make offer to pay (5% or 1/10 loads, etc), or 3) ignore anyway.
Yes. In a word. Typically, each moon will have 4 ore types; one so-called “moon ore” plus three regular minerals. The moon ore cannot be compressed and is most often not mined by any party (difficult to haul away). Similarly, the owner is going to be most concerned to target the highest regular ore eg arkonor, bistot, gneiss etc. This leaves behind a vast field of kernite or veldspar at the bottom rank, but also one of anything else from pyroxeres through to hedbergite. So, if you are not sure, ignore the highest ranked mineral, mine one of the others, and you will never have conflict.
Two final points. First, the yield for regular ores is always highest from HS moon types. Where glazed hedbergite (formerly the highest value ore in HS) gives 10% extra yield on processing, hedbergite from moons gives 15%. And this premium occurs for all versions of regular ores that come from moons. Second, the size of asteroids in moon belts is much bigger than you will find otherwise. Much.