Hello,
Please, either create separate topics for the separate problems or use numeration for your issues. Because posting the problems one by one without numeration and without waiting for the solving of the previous problem may cause misunderstanding.
1) We don’t see the mentioned error with the header settings http://prntscr.com/upddlh What browser do you use?
2) Not all the options are available for the Account mobile http://prntscr.com/updezu We don’t have settings for the mobile drop-down area. Only position of the off-canvas http://prntscr.com/updfvm So, what exactly do you want to change in that popup? Font-size? Colors?
3) What translation is not correct?
4) You used the full-screen layout for the slider. I have changed it to full-width. Check the mobile and desktop version now.
5) Check the single product and single post now.
Regards