Replicate workload from VMWare to Azure using Azure Site Recovery(ASR)

Hello,

I am working on a project to replicate worklooad hosted on a VMWare to Azure Site Recovery for disaster recovery purpose. 

Current Environment:

1. More than 80 VMs hosted on VMWare managed by VMWare Sphere running both Linux and Windows OS..
2. Databases: Oracle DB, Microsoft SQL and MySQL

Requirements: 

1. seamless failover and disaster recovery requirements. 
2. scalable setup
3. No down-time 
4. integrate identity and access mgt. integration with Microsoft Entra ID.
5. RTO < 2 hrs and RPO > 15 minutes
6. Backup:
   •  critical database backup every 3 hours
   • App servers: Daily*incremental) and weekly (full)
   • Transaction Logs: every 10 mins
   • backup config. should be Daily

Questions

• I have confirmed ASR supports fail back from Azure- on premise(VMWare specifically). Hence ASR(Azure site recovery) will be used for the project. However, what is the seamless method to replicate the databases(Oracle, Microsoft SQL and MySQL).     https://learn.microsoft.com/en-us/azure/site-recovery/vmware-azure-failback 
• What is the best approach to replicate the Application Servers?
• integrating existing on-premise 3rd party network security tool for firewall etc instead of the azure cloud native security tool. recommendation??
• cost optimization techniques/recommendations
• Best practices for conducting non-destructive DR drills.