If you have a research-based dill pickle recipe from a reliable source like the ones in https://extension.oregonstate.edu/catalog/pub/pnw-355-pickling-vegetables or from the National Center for Home Food Preservation then adding a few peppers would not be a safety issue.  Some of the recipes add a hot pepper or two for flavor.  The recipe should have at least a 1:1 ratio of vinegar (5%) to water.  

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Nellie Oehler 

Because different vegetables absorb the vinegar/water solution at different rates it is better to follow a pickled pepper recipe instead of adding a lot of pepper to your cucumber recipe. On page 16 you will find a pickled pepper recipe.  You could certainly add dill to this for flavoring if you like.  You will note the proportion of vinegar to water is different than the cucumber dill pickle recipe.  

Hope that helps

Nellie Oehler