Slice the avocados in half around the pit. Remove the pit. Score the inside of the avocado flesh with a butter knife, and scoop out the flesh into a bowl with a spoon. Repeat with the remaining avocados. Add the lemon juice and salt. Mash the avocado pieces against the side of the bowl using a fork until mostly smooth with some texture remaining. Add the rest of the ingredients, and gently fold and stir them into the mashed avocado. Adjust lemon juice, salt and pepper to taste.