Use Case Scenario across multiple Apple devices

I've done some searching of the forum and seen scenarios and suggestions that touch on the below, but perhaps nothing that covers it all off. I'm also aware that some features are being worked on, but perhaps these thoughts will be useful to the Dev Team. Apologies if I am duplicating posts elsewhere on the Forum.

I have an iMac, Macbook Pro, iPad and iPhone. I'm running the current Mac App Store version on my computers and the iOS 8 Version of 1Password on the two iOS devices.

My proposed set up is this:

The iMac hosts my Big Vault - all passwords from everywhere - stored in the 1Password Primary Vault. In this Big Vault I tag some passwords/notes etc with 'mobile'. I want these tagged items to auto transfer to a second vault on the iMac called 'Mobile Vault'.

(Question - is this auto population of a secondary vault based on tagging currently possible?).

What I'd then like to do is to sync this 'Mobile Vault' and only the contents of this vault to my iPhone and iPad, perhaps even the MBP. As I understand it, iCloud sync cannot currently do this with a non Primary Vault, but the feature may appear in future. In the interim would using Dropbox sync for this be the best workaround?

My ideal scenario is add items to Big Vault on iMac, tag some items as 'mobile', have these tagged items automatically appear in my secondary vault, 'Mobile' which then auto propagates via iCloud to the remote devices. The only vault on the remote devices would have the contents of 'Mobile' and adding items to 'Mobile' via the remote devices would in turn have mobile tagged items appear in the Big Vault on my iMac as items synced to 'Mobile Vault' from remote devices are a subset of the Big Vault on the desktop.