I'll try.
First, I don't see any converter in your schematic. Perhaps I don't know what an IBC is.
If you "never" (not sure what that means) plug in, and don't have a generator, how could you power a converter?
Running the entire house on inverter is a nice way to go, but you may be tempted to run large appliances like toaster and MW. If so, I suggest you up your battery voltage (and inverter) to at least 24v. Gets rid of the fat wire.
I don't know why you have 2 solar controllers. You could series your panels, get rid of the combiners and more fat wire, and just have one.
