Prestashop modify

1) I would like the articles to be visible in the store must have at least 19 pieces available. If they have less than 19 pieces they should not be shown in the archive. 2) the TAB key does not work in the filter we created. With other browsers it works but not Chrome does not. What can we do to make it work? 3) in the filter we have developed and in the default one in the product archive we have to remove "seasonality" for motorcycle tires. 4. the "vans" categories must coincide with "car". so in the filter the tab "vans" must be a copy of "car"