Eric, 
You list the very reason to be very careful who you select if you want to participate. ALL of the terms must be clear and written.Even with the most honest and respectable of companies. Things change. Management/ownership,ect.  Oil is no place for gentleman's agreements. We got lucky a while back. Bought a piece of farm ground for cropland. It had an old lease. Turned out there was a very small stipulation in it. Could not be recombined without the landowner's signature. That stopped a second company from running amok with our lease. Your ground is more married to that lease than you are to a spouse.