Hey, thanks for playing the game! If the dev console popped up because of an error, there should be a close button for it. If thats not what you mean, then, I believe Ctrl+Shift+C is the keybind for the console (I had to look it up). I hope that helps!
Also, you CAN tell your dwarfs which units to attack! There's just no indicator to show you that its working lol. I'm adding an outline flash to this soon, so you'll know that you selected the correct target.
Lastly, the suggestion about building rails near enemies is a good one. Enemies can't attack rail anyway, so I might just add this feature :)
Again, thank you for trying the game :)