https://openenergymonitor.org/emon/node/12286
The easy one first: The meter pulses will only give you consumption, you will get no pulses when you are exporting. So although by definition that meter is totally accurate, the pulse output is only half the story. The other point, which might not bother you, is you only know about consumption after the event when a pulse is generated. And of course, resolution is one pulse (1 Wh for your L+G meter).
If you had the 3 emonTx’s in the garage, where presumably you have your meter, Henley Blocks and the PV isolator, you could monitor both PV generation on each phase and the nett import/export on each phase. (The difference of course being consumption on each phase.)
But that won’t give you any details about individual circuits.
It looks as if this will need its own emonTx (Can you confirm it has a single phase supply?) or, from what I know about it, this:
Is this the heatpump monitor that’s presently in development?
Yes, the emonTx/Heatpump Monitor would surely be instead of, not as well as, another meter? The comment above about pulses applies here too.
If the indoor and outdoor units are on the same phase, and fed from roughly the same place, then a CT on each will give you the individual consumptions of the two units.