If you remove the code that registers a post type or a taxonomy you loose the ability to edit them in the back end, the menus are removed and if you try to access those pages edit pages you’ll get a 404. With a taxonomy you will also loose the ability to display them on the front end. Not exactly sure if you can show the post, that might depend on the rewrite rules, but I’ve never tried. If I’m going to remove a post type I generally make sure I delete all the posts first so they’re not hanging about the database.
With an options page, if you remove the code that registers the options page you will loose the ability to edit the options and the link will be removed from the menu and you will get a 404 if you try to access that page. but the values will still exist in the database and ACF will still be able to get them and display them. You could also use `get_options(‘options_’.$field_name’);
If you are still seeing an options page then there is code somewhere that is creating that options page.
