Your second part unfortunately doesn't work at all against trolls. A non-practicing entity - a company that does nothing except hold IP for the purpose of suit

Your second part unfortunately doesn't work at all against trolls. A non-practicing entity - a company that does nothing except hold IP for the purpose of suit, but doesn't produce anything - can't violate your patents, and so can't be countersued using your own patent portfolio. That's why patent trolling is particularly pernicious. Their entire purpose is simply to slow innovation and get rich doing it. Period.