Regarding number 1, not sure what that could be. Would you be able to post what the actual PHP notice says and potentially the stack trace that comes with it if any?
Number 2 was fixed in 4.18.3, in this file packages/cms/form/form_email/form_email_edit_fns.inc on line 1918 the reference to where this popup lives has changed:
From this:
... window.open('<?php echo sq_web_path('data')?>/asset_types/form/popups/thank_you_keywords.php?assetid=<?php echo $asset->id ?>', 'keywords', 'toolbar=0,menubar=0,location=0,status=0,scrollbars=1,resizable=1,width=580,height=520')">list of ...
To this:
... window.open('<?php echo sq_web_path('lib')?>/web/popups/thank_you_keywords.php?assetid=<?php echo $asset->id ?>', 'keywords', 'toolbar=0,menubar=0,location=0,status=0,scrollbars=1,resizable=1,width=580,height=520')">list of ...
You can either upgrade to 4.18.3, change this line manually, or replace just this file.