SQL Always on HA and DR Best practice configuration

Hello, 

your help will be highly appreciated.

I want to configure in Azure  Always-on structure with DR scenario. How do you recommend building this? 

I was thinking about this configuration:

primary site: 

2 DC's: one primary one secondary 

1 FSW server 

1 internal LB for the Listener

2 SQL nodes: one primary one secondary. 

DR site:

1 node Secondary DC replica

2 SQL Secondary replicas

1 internal LB for the listener. 

few questions:

1. all 4 of the SQL nodes will be in the same cluster or should I divide them to another cluster? 

if I'm using the same cluster should I configure the DR nodes for manual failover and primary nodes for automatic?  

2. in the primary site the SQL nodes will be in sync mode and the SQL nodes in the DR site will be configured in an async mode or not? 

3. I have 3 applications running, should I use 1 availability group or 3? 

My main question is if the above configurations suitable for HADR? have I missed something? 

Thanks all!