Sure, you can hunt without guns. I don't really see an argument for not using them though, as long as there's no lead. What's really the ethical or environment argument in favor of only allowing bows, or whatever? I see the emotional appeal, if people have a negative view of guns. Not a logical appeal though, besides maybe making them harder to access to prevent deaths by firearms. If you can ban hunting with firearms, you can also just ban using lead ammo, so I don't see how banning them is the best option in general.
I didn't make any proposals in my above comment. It's entirely statements of observations. I don't know what you mean by saying you don't see how they would work or not. I gave explanations of why hunting isn't negative, and is often positive, but not any proposals of how anything should be done. Would you care to elaborate?