All of those things are possible with IoTaWatt. It would be helpful to have a line drawing to sort this out. While you may have a clear mental picture of the setup, it is complex, and a line drawing will help immensely if you come to needing help.
You have four sources of power right now: Grid; PV; Generator; Powerwall.
If separate loads are running off of different sources, it will be necessary to have multiple voltage reference transformers if you want to see anything but Amps. Again, a line drawing would help to sort that out. Each additional AC reference would use one of the 14 inputs.
IMO you probably should be more focused on Watts as there will be some amount of reactive power moving between loads that will make it impossible to reconcile the various measurements. Watts takes into account the reactive power.
IoTaWatt doesn’t consider any input as “primary”. You can have any size CT on any input.
Info about CT extensions: Extending CT leads with commodity extensions