Hey guys, so I played around with Hungerinpeace, and it honestly isn't doing it for me. The hunger bar and food saturation still acts more like regular peaceful than normal difficulty, and there are no other 1.12 updated mods that will do that same thing. BUT, upon googling around, I discovered there is another way to play without hostile mobs that doesn't require any mods!
Just go into any world- existing or new- set to regular difficulty (anything other than peaceful), and with cheats enabled. Then simply open the chat box and run the command /gamerule doMobSpawning false. It is case sensitive by the way, so make sure you type it exactly how I did.
To my knowledge, this prevents all hostile mob spawns, except for the ones from spawners. This means that you can play in any game mode or difficulty and still have hunger and everything, but no mobs except for those forced from spawners in dungeons and nether fortresses. Sure, it means your game won't be completely mob-less, but it does offer some advantage such as being able to obtain blaze rods and make potion stands and some kinds of potions if desired, and also mob sounds while mining/caving will lead you right to dungeons, making them potentially easier to locate. If nether of those interest you, you can just avoid dungeons and nether fortresses (not that hard), or disable them in the custom settings when creating a new world.
For those who don't like, or can't/don't know how to use mods, I think this is a great option
Oh, and by the way, you know how in hardcore mode when you die there is no respawn? I bet that would be an interesting challenge in a non hostile mob world too, since you can still starve, drown, take fall damage, ect 