This reminds me of the mission in Malhadra where one side must kill civilians, while another protects them. It was a really fun mission so I'm sure this one would be good as well.
Love the fog mechanic; simple, uniform, no need to roll every round, but still very narrative.
Both players get to move the creatures? Even the one trying to kill them? I can see how that's needed for balance, but does it fit the narrative?
I would create your own map. The map shows 3 objectives but the instructions say D3+3. I get that the map is there to give guidance, but some folks might just look at the map and see 3. Plus they might wonder why the 3 aren't placed in a balanced way.