Exchange 2010 Office 365 Hybrid User Sync

Hi,

following situation:

On premise Active Directory:
Domainname: test.local
Additional UPN Suffix: test-online.de
Username: lastname.forename@test-online.de


Office 365 Abbonement:
Domainname1: testnet.onmicrosoft.com
Domainname2: test-online.de
Existing Office 365-User:  lastname.forename@testnet.onmicrsoft.com (Office 365 E3 license enabled)

We configured AADConnect to do following:
- Sync AD Objects with Password (Hybrid-Option-enabled)

Hybrid Configuration is not configures yet.
After an AADConnect-sync, we have following situation:

Office 365 Users:
lastname.forename@testnet.onmicrosoft.com (Office 365 E3 license enabled)
lastname.forename@test-online.de  (no license enabled)

Is that behaviour OK?

What would that setup mean for the upcoming Exchange Hybrid configuration?
Which Account will get the additional @testnet.mail.onmicrosoft.com Address and when will that happen?
Is the Addess @testnet.onmicrosoft.com  used anywhere in the Hybrid configuration? Or can I leave this Account in Office365 parallel to to synced user?

Many thanks in advance!