The short answer is yes.
You can't harm a cast iron Dutch oven with the temperatures generated by a normal campfire.
Ideally you have the type of Dutch oven with three legs and a lid designed to hold coals.
Those were specifically designed to be right in the fire.
The more common type with a flat bottom and domed lid are probably better used by suspending with their bail instead, simply because they're more prone to burning the food when in direct contact with the coals.
However, you can cook perfectly good meals with them by learning how to let the fire die down into nice cooking coals, and how to bank the coals for effective cooking (more like your second diagram).
I have both types and prefer cooking on my three legged oven.
My brother prefers the flat bottomed kind, but he's got the tripod for suspending the oven, and I don't.
outdoors.stackexchange.com/users/3574/delliottg
Yes, you can with no trouble.
I have one that I use a lot direct in the fire.
I built a little fire pit outside at home using regular cinder blocks.
I used a tripod and hang my cast iron pot just above the fire.
I use camping as well all the time in fireplaces like this.
outdoors.stackexchange.com/users/3710/Desorder
You could place it on the fire but you would likely burn the contents.
Putting it directly on the fire is also not stable, as the wood shifts as it burns.
A tripod over a fire is useful for stability and to reduce the temperature.
Coals at the edge should work.
Why not just pull some coals to the side?
outdoors.stackexchange.com/users/6728/paparazzo
Yes, but that would be to use it as a pot rather than an oven even if you used it with the lid.
To use it as an oven, you should put two-thirds of the heat source on the top of the lid (with one-third on the bottom).
Typically, you should use charcoals briquettes as follows to achieve a 350 degree backing temperature:
Bottom has charcoals equal to two-thirds of the diameter of the top in inches.
Top has charcoals equal to four-thirds of the diameter of the top in inches.
For example, a 12 inch Dutch oven would get eight briquettes on the bottom and sixteen on top.
If you left the briquettes there for sixty minutes you would have the equivalent of about one hour in a standard home oven at 350 degrees.
For each decrease/increase of the temperature by 25 degrees, remove/add three total briquettes (one from bottom and two from top).
Of course, outside temperature and wind will affect the Dutch Oven.
Also, to ensure even heating, rotate the entire pot (including top) counter clockwise by 90 degrees every 15 minutes and the top only clockwise by 90 degrees every fifteen minutes.
outdoors.stackexchange.com/users/12465/James Russell
Cast iron dutch oven's can even be burnt in a fire to clean them out.
Aluminum dutch oven's, however, can melt when placed in a campfire.
outdoors.stackexchange.com/users/9732/deltajuliet
Most of the guides I have found relating to  Dutch ovens  recommend placing hot coal on and underneath the oven, or hanging the oven from a tripod.  I was wondering if my cast iron Dutch oven could be placed either on the fire directly or on the wood coals at the edge of the fire. I have included an illustration to help.
Can I place a Dutch oven directly into/next to a camp fire?
outdoors.stackexchange.com
<camping><camp-fire-cooking>
outdoors.stackexchange.com/questions/14606
outdoors.stackexchange.com/users/11611/user6122771
Yes, you can with no trouble.  You can't harm a cast iron Dutch oven with the temperatures generated by a normal campfire.  Make sure it is stable, as the wood shifts as it burns. Also, be careful not to burn the contents. There is a risk of burning your cooking, otherwise there is no reason not to do this.
You can do this with no issues. Doing this may cause you to burn what you're cooking.