To answer the main of your question, it doesn't matter because the Media Creation Tool will format it to whatever format it needs it to be.
To help with your dead flash drive, what did you use to format it? I would use diskpart, which is a program that can be interfaced with via command prompt.
The instructions below pertain to the flash drive that has become inoperable after the attempted format to NTFS.
To use diskpart, open command prompt as administrator, then type in diskpart. Command prompt will become the interface to the diskpart program. Next, enter the command "list disk". It will reply with all disks. Then select the disk that has the same capacity of the flash drive by entering the command "select disk [number]". Do not include brackets. It will reply saying that whatever number disk is now the selected disk.
Now that you've selected the right disk, enter the command "clean". Clean erases all contents of the disk, even the partitioning information. It will reply that it has successfully cleaned the disk. Next, enter the command "create partition primary". It will say that it has created the partition. Now enter the command "select partition 1". It will reply that it's created the partition.
Now we've created a partition, so let's format it. Enter the command "format fs=ntfs quick". It may take a few minutes to execute this command. It will reply that it has successfully formatted the disk. Next, enter the command "assign" to give the disk a drive letter (F:\, G:\, etc.). A window may appear at this point showing the empty contents of the flash drive. Close any window except for command prompt.
Now, we need to exit diskpart and then exit command prompt. Just enter the command "exit" and it will say "leaving diskpart..." and you're now back to a standard command prompt. Enter the command "exit" again and the command prompt window should close.
I hope this helps.