I agree with the deadlifts. Haevy deads without straps (that is important) have thickened up my neck over the years.

Also the head/neck harness is an option. Id be interested to see proven studys on their being problems like you listed OL. Not saying theyre unfounded I just have never heard of it.

Wrestlers do a lot of work with bridging to strenghten their neck but im not sure what physical effect that could have.