According to the Nutanix Community1, host maintenance mode is used to safely migrate all the user virtual machines (VMs) in the host and make sure no VMs are running on the node. If a VM can't be migrated to another host, you need to shut down the VM for the host to enter into maintenance mode.
According to The Virtualist2, a storage container is a logical segmentation of a storage pool that can be mounted as an NFS datastore on ESXi hosts. You can choose a replication factor (RF) for each storage container, which determines how many copies of data are stored across different nodes.

Deduplication is a feature that reduces space usage by consolidating duplicate data blocks on Nutanix storage.
Deduplication can be enabled on a storage container for either cache or capacity, or both. Cache deduplication is performed on the data in memory and SSD, while capacity deduplication is performed on the data in HDD. Capacity deduplication is not enabled by default and is available if you have purchased a Pro or higher license2. When you enable capacity deduplication on a storage container, it takes effect after 60 minutes3.
This delay allows the system to identify the best candidates for deduplication and avoid unnecessary overhead.

According to Nutanix Support & Insights1, image create, update, and delete (CUD) behavior depends on whether a cluster (also known as Prism Element) is registered to Prism Central. Images created on a Prism Element reside on Prism Element and can be managed from Prism Element. For better centralized management, you can migrate images manually to Prism Central by using the image import feature.

A VM-VM anti-Affinity policy is a rule that ensures that two or more VMs don't run on the same AHV host. It's useful when an application provides HA and an AHV host can't be an application's single point of failure1. In this case, the SQL cluster VMs should have a VM-VM anti-Affinity policy configured to prevent them from running on the same host and causing an outage if that host fails. A VM-VM anti-Affinity policy can be created using the aCLI commands2. The other options are not relevant for this scenario.