All contents in the visual landing page designer are responsive. Since the layout is free-form, the contents will be displayed as mobile responsive in the order in which the contents are added to the landing page. If your content is appearing out of order on the mobile device, it is likely due to lower elements loading in before upper elements because of the order they were placed. As such, it's best to create your landing page from the top down (logo on top, contents, form, etc.).
Lead Liaison's Layout Template tool automatically converts all resources from relative paths to absolute paths. The HTML WYSIWYG editor is primarily intended for small snippets of HTML to pop into a Layout Template along with a form.
My elements are appearing out of order on a mobile device
When the landing pages switch to responsive mode, elements are loaded in the order that they are placed on the page. For example, if you place a form on the page, and then a text box above the form, the form will load first and may push the text box down. To correct this, simply re-place the elements in the order they should load on the device. In general, it's best to create landing pages from top to bottom.