If a single-phase 240V inverter is connected to the US 120/240V split-phase grid, it needs 2-pole disconnect if connected to the 240V lines.
If the inverter has Line/Neutral with a single pole disconnect, what I would do is put a transformer on the input. This could be 240V to 120/240V isolation transformer. Or, it could be an auto-transformer. But not your usual 120/240V auto transformer. It would need three, 120V windings in series making -120V, Ground, +120V, +240V. Same on the output for your loads.
Yes, connecting two current transformers to two lines of split phase should work for an inverter with only one CT connection. But you might have to play games to get it to read watts correctly, if doing anything other than zero-export. Maybe divide output voltage by two, or parallel rather than series connect the two CT.