Blessing's to all here,
I believe Joshua would have been overwhelmed with such a great responsibility and the thought of filling the shoes of such a great man as Moses. There would've been doubt, fear, street, depression and the fact that Moses was gone would've been enough to be shaking in his sandals.
To 'Be strong and courageous' means to be confident in your decisions within your own mind, to keep moving forward "No Matter What" because God gives us the promise, and He always follows up with instructions or commands of what we ate to do. So, with that we are to 'Walk in Faith knowi g we have the Victory.
The distinction I would say is in understanding and recognizing whatvlies in you. I am reminds of Paul in 2nd Corinthians 12:9 where our strength comes from the LORD when we are weak or in our weaknesses. Joshua knew and had seen both in his walk with Moses and the LORD.
The relationship between fear and faith, is unbelief, doubt, confidence and faith. In order to stand on Faith we need to First Address Issues That Hinder us to move forward in confidence.
Hmmm. To be courageous is to be determined in one's decision, where fear brings doubts. So, I will say 'no'. The only Fear we are to have is of the LORD.