hi, below are the answers for you quetions:
1.about slider white farme: to remove the frame, open file panda/funtions/layerslider/skins/defaultskin/skin.css, remove line 5
-load slider images may take some time, so this is the normal loading process. I think there is no better way to avoid it
-change the background color of the menu section here: appearance/theme options/color settings/header section
-change background color of the pages here: appearance/theme options/color settings/content page section
3.align centered text: edit your page, mouse over your text block in visual composer editor, click pencil icon, dialog box will show, text align toolbar will there.
4.show page title: edit your page, check option ‘show title in static page’.