I'd say this is probably the correct place to ask as it's a Kobo related issue.
You are essentially talking about cloud sync of various things. At present Android does not sync your notes or highlights to the cloud. iOS *does* sync notes and highlights to the cloud.
If you had an iPhone and an iPad and you made a highlight or a note then it *would* sync between those two devices.
If you have an iPad and an Android phone and you make a highlight or note on Android it will not sync to the cloud and will not appear on your iPad. If you make a note or highlight on your iPad then it will sync to the cloud, but as Android does not pull these down you will *not* see it appear on your Android device.
When it comes to the page being read (cloud bookmarking as we term it), this *does* work on both iOS and Android. Here's a little something I wrote about it:
Does the app sync the position in the book across devices?
The application does include this type of functionality, internally referred to as "cloud bookmarking". If you are actually reading through a book, then at that point it is not instantly going to send the position in the book, however, if you suspend or quit *the app (press the home button on the device), or the device goes to sleep (auto-lock), or you manually exit the book, then we will attempt to send your position in the book to the server. If you don't have any network connectivity at that point then we obviously cannot send the information up, and we don't cache it to send up later.*
Please note that this sync will ONLY work for books purchased from Kobo and that are part of your Kobo library. Books that have been "side-loaded" (added using iTunes, Dropbox, Safari, or any other method that allows you add a book to the Kobo app) will NOT sync their bookmarks between devices.
One key thing to note here, the "bookmark" is the page position, it is NOT the little dog-ear icon that you can make in the top right-hand corner of the page. These "dog-ears" do not currently sync (certainly they don't on iOS, and I am pretty sure they don't on Android). It is confusing as the page position and the dog-ear can called "bookmarks" depending on who you speak to.
I hope this helps explain things
