I should have said, no additional guidance. The picture and purpose of the Blue Candle is in the instruction manual. It's clearly a permanent item.

https://miiverse.nintendo.net/posts/AYMHAAABAADMUKlYz1zqxQ

Aonuma says:
"If you noticed something strange with this picture, you’re quite the Zelda fanatic! That’s right, shops in the past Zelda games sold things that would run out once you use them like arrows and bombs, items that needed replenishing. They have never sold an item that doesn’t go away after each use like the boomerang or the hookshot."

You can lose your sheild repeatidly in the game and the blue candle is replaced by the red candle.

The candle still "doesn’t go away after each use" like Aonuma said. Also, would you said the sword is not a permanent item, despite being upgradeable?

So what happens if the boomerang in A Link Between Worlds can be replaced by a magic boomerang?

Don't answer, because this is getting silly anyway. The actual point in ALBW is that a large number of permanent items are up for sale which should mean that the world will open up depending on your choice of what to buy first. Although it's perfectly possible that the amount of rupees needed for each item more or less forces the choice on the player.

So what happens if the boomerang in A Link Between Worlds can be replaced by a magic boomerang?

Don't answer, because this is getting silly anyway. The actual point in ALBW is that a large number of permanent items are up for sale which should mean that the world will open up depending on your choice of what to buy first. Although it's perfectly possible that the amount of rupees needed for each item more or less forces the choice on the player.

It does mean the predictable miniboss -> item -> item related puzzles -> item related boss structure has to change. They will have to plan for you having various combinations of items in your inventory, which will lead to a lot more unintended advancement (a very good thing).