The salt is always optional unless you are fermenting things as it is the main safety factor in fermenting.

But for fresh-pack pickling recipes you can leave it out although it does add a bit of flavor and crispness in some cases. It doesn't affect how long they will last.

As to the sugar, it is primarily used to take the edge off the vinegar's sharp flavor. It doesn't turn them into "sweet" pickled peppers.

The primary safety issue in pickling peppers is the ratio of vinegar to water called for in the recipe. The other issue that concerns many is the crispness of the pickled peppers which is why using Pickle Crisp when making them is often recommended.

There are many discussions here about pickling peppers, some with recipes, and additional recipes are also available at NCHFP.

Dave

Here is a link that might be useful: Pickling vegetables including various peppers

Thanks Dave for explaining everything