AIP, DLP, o365 Labels

[Taen keren]

Hi
Can someone point me in the right direction for information about:

1. how existing documents are classified both on-prem, SharePoint Online, OneDrive (Azure Information Protection(AIP)? AIP scanner ? Auto-apply labels? -
2. Are there unified Labels now? - so I only define the labels in AIP ? 
3. What are my options  with DLP / data loss prevention when using AIP?
4. What options for encrypting documents and mails from mobile devices when using AIP?

When using AIP and policies - is that it? - no need for doing it anywhere else? (AIP 'overrides' everything else?)

[#2]

Taen, you might want to look at this recent Microsoft Ignite presentation (recording & slides) on label strategy & roadmap (aka Microsoft Information Protection): 

BRK2006 - Use Microsoft Information Protection (MIP) to help protect your sensitive data everywhere,...

A good slide that paints the high level picture:

[#3]

Hi Christophe 

Thx  ;D 

Maybe I've missed something, but in that Session/Slides it's mentioned several times: 

M365, MIP, M365 Analytics...M this and that....

So a pre-req are a M365 E5 subscription? - and if I don't have a M365? 

I will not have the Unified labels option and the centralised Admin center and I still need to do the 'work' in Azure / AIP and Office365/labels or? 

The Admin centers shown in the slides are different from mine;
in My 'Office 365 Admin center'  https://admin.microsoft.com 

I have the:  

'Microsoft 365' Admin Center in the top bar - but in my 'Security and Compliance center' https://security.microsoft.com 
I have the 'Office 365' Security & Compliance Center' in the top bar