question

Hi @CYAN,

it's mentioned in the manual:

Note - Bluetooth functionality is limited to the features mentioned above. It is intended to be used to assist with initial connection and networking configuration. You cannot use Bluetooth to connect to other Victron products (e.g. SmartSolar charge controllers). For more information about how to connect other Victron products, please see Connecting Victron products

Maybe there is something coming in the future, but definitely not yet.

The Bluetooth functionality is designed for easy configuration using a phone or tablet etc. using VictronConnect.
The Bluetooth functionality in the CerboGX is to aid in initial configuration of the networking settings using VictronConnect.
The Bluetooth also offers VE.Smart networking for small systems where there is no central "hub" like a CerboGX. The low bandwidth capability of Bluetooth its self only allows a small amount of data to be exchanged within a VE.Smart network. Typically just Voltage, temperature and synchronised charging.

Once you have a CerboGX then there is no need for VE.Smart networking anymore. The CerboGX also offers VRM connectivity which VE.Smart Networking does not do.
The devices need to connect with cables in order to convey the full set of information from the device to the CerboGX. Also in a system of this size the CerboGX may well be sending control messages to the devices. Hard copper cables are best for this sort of communication.

I'm not sure why your dealer did not inform you of what I have just explained, they should have.
I don't think there is wasted money, you have almost everything you need to install your system.
Am I right in thinking that the 2x "smart battery connects" are "Smart Battery Sense" modules? If so, you can tell your dealer to take those back, they shouldn't have sold you those. There can only be one source of Voltage measurement, this will come from the SmartShunt.
Get 3x VE.Direct cables to connect your 3x MPPT's to the 3x VE.Direct ports on the CerboGX.
Get 1x VE.Direct - USB cable to connect the SmartShunt in to one of the USB ports on the CerboGX.
The MultiPlus connects to the CerboGX with a standard UTP network cable, the same type of cable that you would connect between your router and computer.
Orion DC-DC can work stand alone.