With respect to your third point, there are already a stack of other browsers on iOS. I don't see why Chrome would explicitly be excluded, compared to them.
I believe all the existing iOS browsers are just wrappers around a Safari web view. While Chrome and Safari do have a lot in common through their Webkit heritage, I doubt Google would bother shipping a build of Chrome for iOS, if it was limited to being a re-skin of Safari.
This is not the case for Opera.
- Nexus tablet is on the way, don't worry, Google will put it out.
- Chrome is already on Android, and the codebases are being merged right now in the chromium tree.
- Chrome will never be on iOS as long as Apple doesn't change the rules. Simply because it can interpret other programs via internet (with javascript) and this is forbidden by iTunes TOS.
- we might see a preview of Android 5 at Google I/O, but will have to wait the end of the year to see it ship.