It has changed. A Finnish company called Digia owns Qt completely and is the main developer. That's why Qt is now available even for Android and iPhone. The Nokia-MS deal does not affect Qt.
Visited link coloring work on my Mac Safari 5.1.7. You can easily try it on your own browser by going to google.com and clicking a search result there. The link changes color.
- Site should work even if the page is zoomed in (e.g., visually impaired people may do this). There are two kind of zooms in browsers, one zooms the whole page pixel by pixel. The other one zooms only fonts. It is usually tricky to get the font zooming look good.
- Some people use Screen Readers to browse the web. The web site should have easy navigation and have text for all non-textual content. See http://webaim.org/techniques/screenreader/
Also, you already mention responsive design for various screen sizes. You could mention that it means the pages should look ok on tablets and phones.
EDIT: I just can't stop... one more thing: The page should load fast even for users who are using 3G networks