The property is posted
I have no idea what you mean by this.
and has a timber manangement plan. There has not been any cutting or thinning for the past two years.
Not sure why this might be relevant.
We will be interviewing the hunters and only allow as the most three or four exclusive rights.
If you're allowing three or four people to do this, then the rights granted aren't exclusive.
No one can bring friends or any others with him or her.
Of course they can. I assume you meant to say that your agreement prohibits bringing others, but those are very different things.
There is liability insurance that I could purchase for $1000/year but the attorney said that I should be covered by the Release and Waiver of Liability agreement that he sent me. . . .
Are we covered and have we thought of everything to prevent a big lawsuit in case somthing happens?
First of all, I'm not sure who "we" are.
Second, as politely as I can think to say this, any attorney who tells you that you don't need liability insurance for something like this because you will be obtaining liability waivers is an absolute moron (and that's especially so where the liability insurance will cost less than $100 per month -- although you didn't say how much coverage you'd be getting, so I can't tell if that's a good price), and I would not even trust that he is competent to draft a decent liability waiver. In a situation such as you have described, liability insurance would provide two primary benefits. First, it will pay up to the policy limits for covered occurrences. Second, if you get sued, it will pay for a lawyer to defend you. While a good liability waiver might mean that you would ultimately win any lawsuit that might be filed, it might cost you $20k or $50k or more to hire a lawyer to defend you in the lawsuit. Without appropriate insurance coverage, that money comes out of your pocket. With appropriate coverage, the insurer pays those costs. So...do you feel like gambling?