Final Showdown: A Link Between Worlds

So I am to that part of the game now where I will be heading to the final dungeon in the game.  I was trying to go for 100% before I got there.  I found of of the Maiamai, but I was unable to get all of the heart pieces (not able to find four).  I got all of my weapons upgraded and found the Hylian Shield.  I believe I have all of the items, even though there are still three free spots in my inventory.
Now I am standing inside the entrance of Lorule castle waiting to take it on.  I will be finishing this another day though, especially if I find out how to get those last four heart pieces (even though I probably don't need them).