Hello,
“I can’t even find out the member login area to test the password resend email button” – it should be the same page that always, isn’t it? just copy URL of the page to be able to open it and do the test.
” I don’t really understand how to move the widgets before switching” – not move, just open https://lady***a.com.tw/wp-admin/widgets.php page before activation other theme and pin it, after doing tests and activation XStore back, go to Widgets page in a new window and compare content on widgets area. In case some widgets changed their positions, you will be able to set them as it was in the pinned tab.
Regards