@Twitch-Variann I will not comment on all the items you list because I am not working on them to be automatically saved neither I know if there’s any readblocks to implement them or not, and, for Unreal 4 the v3.5.0 of this plugin is pretty much the final version.
It’s possible to manually setup properties to do all the things you are asking (just create some custom variable in a blueprint and mark it ‘Save Game’ flag), but I might add automatic processors for them in the future, for example I have in my todo auto records of Blackboard data, but it’s a maybe.
Save system does not control the state of animations (they are multi threaded).
What the plugin does is save/load variables that you create on your animation blueprints and mark them ‘Save Game’ flag (and has a Serializable Interface).
Depending on how you setup your State Machine conditional transitions, the results are the same as if the current state was loaded from disk.
I’m sure World Composition will be deprecated.
For now I am working on runtime save/load support for Unreal 5 World Data Layers:
World Partition - Data Layers | Unreal Engine Documentation