You could cobble most of this together.

You could probably get notifications using org-alert.

Emacs does a reasonable job parsing most html including emails to text, but occasionally you may need to view in browser if it's very html heavy. You can compose html emails using org mode syntax with org-mime.

PDFs are rendered as images. So you have limited emacs functionality, but it does a good job rendering PDFs. Doubt you can do forms.