The charge controller may use a bit also. Especially if it is a fancy bluetooth enabled one.
Same with your battery sensor itself.
And some lithium ion batteries have protection inside, which also uses a tiny bit of power.
Yes, the inverter will use current in standby.
Usually < 1%. Depends on size and brand of inverter.
Also, you can get "load sensing" inverters, that only use 1W or so when idle.
Most of these builds assume you leave the solar panels outside, so the little current here and there is irrelevant.