HPE System Update Manager (SUM) is the recommended method for updating firmware on HPE Superdome Flex systems, especially when HPE Persistent Memory firmware needs to be updated. HPE SUM ensures that all firmware components are updated correctly and consistently, reducing the risk of compatibility issues.
Reference: HPE Superdome Flex Firmware Update Guide

A logical interconnect group in HPE Synergy is used to define a consistent network configuration across multiple frames. The HPE Virtual Connect SE 100 Gb F32 Module for Synergy allows for logical interconnect groups to span across multiple frames. This is because the 100 Gb module supports high-speed connectivity and the necessary infrastructure to maintain consistent network configurations over multiple frames, which is essential for scalable and flexible Synergy environments.
Reference: HPE Synergy Logical Interconnect Groups

In HPE Synergy, a management ring can indeed contain mixed frame link module (FLM) configurations. This means you can have a mix of 2-port and 4-port FLM modules within the same management ring without needing to replace the existing 2-port modules. This flexibility allows for gradual upgrades and scalability within the management ring.
Reference: HPE Synergy Management Guide