Up to your questions:
1. By design, the css class will be applied to the font element (or a span if convertfonttospan is set to true). Your scenario is possible by modifying the ToolsFile.xml and provide custom paragraph styles to your "Paragraphs" dropdown:
| <paragraph name="<H1>Heading 1</H1>" value="<H1>" /> |
| <paragraph name="<H2>Heading 2</H2>" value="<H2>" /> |
| <paragraph name="<H3>Heading 3</H3>" value="<H3>" /> |
| <paragraph name="My Custom Paragraph" value="<p class='myclass'>" /> |
2. This functionality is enabled by default - you need to use the Clear Style option from the dropdown (see attached screenshot).
3. Can you please elaborate some more on that? What exactly do you want to achieve?
the Telerik team