Bricks, Masonry, Asphalt and Concrete - Fire Pit Questions

I am building a fire pit in my yard.

I have a few questions.

1. I am going to use concrete bricks meant for retaining walls. I was told by the person at the stone quarry to use an adhesive to bind the blocks to one another. Some sites I checked said that the adhesives won't stand up to the heat and can give off toxic fumes. Would this still happen if I lined the pit with fire brick, placing the fire brick directly onto the exposed surface of my "wall" with mortar?

2. If I just dry stack the wall, will it likely crumble due to ground freezing/thawing? (I live in Wisconsin).

3. Is there any heat resistant adhesive?

Thanks,
Bill

Refractory mortar is what is used for firebrick.