1. reverential - expressing reverence, reverent; inspiring reverence.
reverent - marked by, feeling, or expressing reverence.
There's no special difference. Although, reverent is more likely to be used to describe a person, whereas reverential would stand better with things.
2. John lied (lay) recumbent and unconcious. (You describe John)
3. As after all I was not a bad little boy but I was shy and covered it up by bravado.
I'd need more context to tell you why. But I think it can be left out, no matter what the context is. Still...
Student or Learner