Every one of those sentences could be said by someone and would be correctly understood. When there is a mixture of singular and plural nouns, it's usually best to provide the article before the noun. Also, clothing is a bit strange because while there are plural words, like jeans, it still refers to a singular object. Also, boots (while plural and technically referencing two things) is commonly viewed as a single thing--a pair of boots.
All that to say, clothing isn't your best example to try to figure out the correct rule here.
In general, when you have a bunch of items, you can either reference the number before each item, or you can group them by items. Suppose, for example, that you had one bookmark, one ruler, one computer, two pencils, two pens, and five sheets of paper. You could say: "I have a bookmark, ruler, computer, two pencils and pens, and five sheets of paper." The "a" before the word "bookmark" will carry through for each item until you specify the change in the number.