Hi,
just to give you a short answer (don't blame me, if I'm not totally right).
1) Sorry.
2) As far as I now, there is no way to do this. It's just a Webfrontend to read and write mails, without saving to a folder. But let us dream a little bit: If RC could open the Outlook pst format, read it and save new mails in there, I probably will not use Outlook again
But then, we have to take this file anywhere, we go... better a big IMAP Server account...
3) RC polls. I guess, every 2 - 3 minutes?! You can see this on the green flashing banner top middle of the page, but I haven't looked so far, if you can change this polling time easily.
Hope, this it a first answer worth...