It seems that making a new mine that inherits from the default mines (Minemine and MineMineE) doesn't work. Arma complains with all the "no entry..." errors. The issue APPEARS to be that the MineGeneric vehicle - which is the (private) parent of the mines in the cfgVehicles section - is a "root" object. It doesn't inherit from default; it is simply "class MineGeneric". So I tried adding the mine as a Buoy - no problems. It is a mine-shaped buoy! This is it ingame as a mean-looking buoy:
Anything I do trying to get the mine to appear in-game either generates the "no entry" errors or causes an access violation. I looked at other mine addons, and no one has done what I am trying to do... inherit from the default mine configs. For example, JTD Mines uses a nonstrategic "Thing" object, and scripts. The SC9 naval buoy (from Arma) used a trigger in the init to damage nearby vehicles. If there's a mine object that inherits from defaults I've overlooked it. So it seems to me that the default BIS mines are hard-coded in such a way that hinders the addition of more mines.
Here is my config - as you can see, it is copied/pasted from the default mine configs. I've tried several different iterations (including changes to the inheritance as per the weapons_e config) and nothing changes the behavior. The issue is always a problem with the Vehicle section.