Why would you want a 4 gang box? Why the usb? Why use wire nuts on the last neutral and hot?
You wouldn't normally cap the grounds on romex, just twist them with linesman pliers. and they would all link to the incoming line.
And if you were capping ground it would be green.
But I've never wired a 4 gang box, and I'm NOT AN ELECTRICIAN....so take it for what its worth.
but yeah technically it will work.