Configuring AlwaysONAG on the SQL Server 2016 in Windows 2016

I am going to set up AG & # 39; s for the first time, so with little or no experience, guide me in understanding below:

If I am configuring 4-node AOAG with the following scenario:

Node1-NY Data Center – Primary Replica

Node 2-NY Data Center – Secondary Replica

Node1 — Node2 Synchronous mode

Node 3 – Secondary replica of the Michigan data center that acts as a DR site with different subnets with ASYNC mode

Node 4 – Secondary readable in the NJ data center for reporting purposes using the ASYNC mode

Doubts questions:

  1. In the previous configuration of Multiple Subnets, I can continue using a different storage in 4 nodes or I need to use SAN replication because I have read some blogs and it is confusing if that is a requirement for the sending of multiple sites

  2. What should be the ideal configuration of the quorum? – Can I have that on the NJ site as a witness of shared files?

Also, if there is a better design than the previous one, suggest me, since I have never implemented or worked in AOAG before.

RPO / RTO for critical applications varies between 2 hours and 4 hours

While for mid-criticism it's between a day and 2

I can add information as needed.

Thank you