OK, first point, you should be able to use our “standard” c.t. on the each of the 240 V circuits, but you will need a larger aperture c.t. on the two service entrance wires. You don’t need a c.t. on the neutral - all that would tell you is the difference between the two legs, and if you want that, it’s cheaper to do it in the maths.
Second, you don’t normally need two c.t’s for the 240 V circuits. Even if those are appliances or plant that has 120 V controls, the current/power drawn by the 120 V part is usually insignificant when compared to the main load, so there’s no real gain in measuring the current in both legs - just measure one and double it (or double the voltage, not both, because you’ll be measuring only one 120 V leg). But of course you must measure both service entrance wires, because the 120 V circuits won’t be balanced.
If you put an ISM band 433 MHz radio in the basement, will another in the garage be able to transmit to or receive from it? In other words, how underground and how thick and what construction are the basement walls? What about the garage walls, and how far away is the garage?
Do you have Ethernet or Wi-Fi to the garage?
This will work IF you can have a radio link between the basement and the garage.
If your basement is underground and you’re unlikely to be able to set up a radio link, then it looks as if the emonPi is a non-starter and you should replace it with an emonBase at a location where you can have a radio link to both the basement and garage, and you have Ethernet. The emonBase is a Raspberry Pi with the radio receiver added (or if you like, an emonPi with no energy monitoring, but it runs on exactly the same SD card and gives you emonCMS). Then you’d want an emonTx in the garage using two inputs (EV and PV), you’d need a further two emonTx’s in the basement on the two Service Entrance Wires and the three 240 V circuits - and you’ll have 3 spare channels unfortunately.
Each emonTx will need an a.c. adapter to measure the voltage and power it, the emonPi needs an a.c. adapter to measure the mains voltage, and it and the emonBase need a good 5 V d.c. power supply.
And of course, you need the c.t’s.
We need to get an expert on the Solar PV apps to confirm that they can be set up with the data arriving from different places, but I’m almost sure that’s OK.