Long story short, I don't like killing dogs no matter how mutated they are and got really, really tired of manually disabling every single hostile dog using the console. I made a similar mod for Fallout 3, so I had some idea of where to start. I made two versions: one that set the spawn chance for hostile dogs to zero, and one that made them non-hostile. The latter worked much better, so I worked on that. 

This mod does the following:

• Changes the AI attributes of guard dogs and mongrels to no longer attack (nearly) anything on sight
• Guard dogs and mongrels will "help nobody," which reduces the possibility of aggro for both types and makes guard dogs very bad at their jobs
• Set generic guard dogs and mongrels to "Protected" so they don't die to random NPCs
• ViciousDogFaction (aka mongrels) is no longer an enemy to DogmeatFaction
• The wounded dog from the random encounter is now set to "Essential" so you can't accidentally kill it
• Junkyard dogs are also set to Essential, so they're unkillable
  

The Nuka-World version also:

• Adds the changes listed above to Pack dog NPCs
• Removes the cage fight spawn points in Bradberton Amphitheater (sets them to "initially disabled" for compatibility reasons)
  

Essentially, all previously hostile dogs will ignore the shit out of you. They won't help you in combat, and if you attack them, they will aggro on you. (So mind your grenades around them.) 

(Note: I know that Animal Friend is one way to make these NPCs non-hostile, but it's nearly as inconvenient as using the console if you want to pacify every single one of them)


Installation:
It's just an .esp, so just stick it in the data folder and enable it or just use NMM.

The misc file is a simple batch file that gives you all gear that drops exclusively from dogs, like collars and dog armor. Some mods (like Armorsmith Extended) let you craft these, but this works as an alternative way of getting them without killing dogs.

Compatibility:
Any mod that touches the records for feral dogs, guard dogs, junkyard dogs, Pack dogs, and/or unique dogs will conflict with this one. If you point me to a conflicting mod, I'll try to make a patch. Mods that edit ViciousDogFaction will also conflict. Anything that messes with the spawn points in the Bradberton Amphitheater will conflict with the Nuka-World version.

Future plans:

• Make a version that makes all dogs Essential so they're impossible to kill by accident.
• Make a version that increases dogs' HP significantly so they're harder to kill by accident.
• Make a version that applies to Mutant Hounds.
  

Mods similar to / that go well with this one:

• If you have Far Harbor, I'd also recommend using Friendly Wolves by Neeher. 
• For a similar mod that affects cats, there's Immortal Cats by GenaTrius. 
• For dogs that run away from you instead of ignoring you, try Less Aggressive Animals - Dogs by jackstarr.
• Ven's Feral Dog Replacer by Venezie gives you healthier-looking feral dogs. 
• No More Sanctuary Dead Dog and Raider by kagstrom2100 removes the dead dog outside Sanctuary. 
• Diverse Dogs by eskanonen makes dogs more varied. There's a patch to ensure it works with NMDD.
• If you want to tame dogs, you may want to check out Beast Master - Creature Companion Overhaul by steelfeathers. Load that mod after this one- there is a conflict, but letting Beast Master override should be fine. 
  

I looked into making a version that works for Far Harbor, but since the Trapper dogs, the only hostile dogs in the DLC, use templates modified by this mod, they should be affected even with the regular version :)