For (1), I can paste directly into a compose window
provided the message is formatted as HTML. Either use the popup to do so, or set a default via Preferences > Mail > Composing.
Note: tested under Mac OS 10.6.2 with Safari 4.0.5. If you have a different OS or browser, your mileage may vary.
For (2), what you're looking for is sort of like
Bug 12845 – windows explorer shell plugin "send this to mail recipient" but I think you're more likely to see results on
Bug 37462 – Support "Send To->Mail Recipients" on windows, which is focused specifically on Zimbra Desktop.
Read through the second bug, it has some links to further discussion.