Some of us have doubts about what we write. Yes, we do have doubts because it comes down to what the crowd see in our work and the other part comes down to what we see. It gets muffled up at times. I suppose you shouldn't stress about the question your asking. Just write something and take it.
You have to see the words on each page. Take a long look and see if each one fits. Its not that the words are not natural. Its that you have to make the words fit with one another.
Your stuck like some writers are at a certain point. You can do some research. I would just find something to gaze at. Find something to make the character come to the way your looking for.
You could put some in the middle or some in the end, but you should do what you feel you should do. Let the reader deal with the lore being in different places. It is fun to put lore in hidden places.
You can mention something happening such as the landscape changing or the sky changing. It doesn't have to be landscape. You could mention something connected to passing.
You want to show people what you have written later on. Keep the stories to a low number. The number of stories you start with a couple chapters. As for you getting stuck, you got to realize you not the only one who gets stuck. People of all ages get stuck. Wait until your in the feels for it to...
You should not have more then you need. You don't want extra characters in the story. Unless, the story calls for some extra characters to perform a action.