None of these modlets should affect an existing game, assuming you take the necessary precautions:
Ammo Crafting: Remove any bullet tips or casings from storage/crafting queues.
As an aside, you should ALWAYS back up your save files before installing a new modlet, just in case something goes wrong.
I've installed all of these mods mid-game (solo and co-op, haven't tried a server), and not had any issues, but I, like any mod author, cannot guarantee that their wont be any problems - It all depends on what other mods you're running, and whether the game decides to play nice or not.
If you're thinking of using the Ammo Crafting Modlet, I'd suggest waiting until early next week, as there is an update coming, that alters shotgun ammo crafting.