Based on the exhibit which shows an NX-3160 block with marked slots, the correct slot for installing a new node in the existing NX-3160 block is slot 2. This configuration is typically aligned with the chassis' design for orderly expansion and maintaining balanced power and cooling distribution among the nodes.References:
Nutanix Bible, Nutanix University NCS-Core 6.8 learning materials

Ref: https://portal.nutanix.com/page/documents/details?targetId=Files-v3_6:fil-file-server-quotas-c.
html#nconcept_amp_xsm_bx

The issue where users can mount all three storage containers despite the intention to restrict access to just container-1 typically stems from a Global whitelist entry. A global whitelist allows all entities to access all containers unless more specific restrictions are applied at the container level. To correct this, specific whitelist entries need to be configured for each container to define and restrict access appropriately.References:
Nutanix NCS-Core 6.8 training resources, the Nutanix Bible, and Nutanix technical documentation on storage container management.

In the preparation for a new cluster installation, after ensuring that the basic physical requirements such as space, cabling, and hardware connectivity are met, it's crucial to confirm power requirements. For enterprise installations, particularly where high-powered equipment like a four-node cluster is involved, ensuring redundant power is critical. The question specifically mentions "redundant" power, suggesting the need for a high-capacity solution typically found in 208v configurations in data centers, which provides more power efficiently and is standard for high-density computing hardware. Therefore, redundant 208v power should be confirmed as available onsite to support the new cluster's power needs effectively. References: Nutanix Certified Services - Core (NCS-Core) training materials and installation best practices available through Nutanix University and the Nutanix Bible.