Create Windows 10 installer USB without bootcamp

I have recently wiped my hard drive and partitioned my hard drive like this:

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            143.4 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data WINDOWS                 40.0 GB    disk0s4
   5:       Microsoft Basic Data Linux Boot              999.3 MB   disk0s5
   6:       Microsoft Basic Data Linux Swap              17.0 GB    disk0s6
   7:       Microsoft Basic Data Linux                   48.8 GB    disk0s7

As you can see partition 1 is the EFI partition (default when choosing GUID)
Partition 2 is my El Capitan partition
Partition 3 the El Capitan recovery partition
Partition 4 is where I would like to install Windows
Partition 5 is where I am going to be able to boot Linux from (tutorial here)
Partition 6 is going to be the Swap partition for Linux
And finally partition 7 is going to be where the Linux (mint) OS is going to be installed.

Due to having this layout (created by doing diskutil partitionDisk /dev/disk0 GPT JHFS+ First 10g JHFS+ Second 10g JHFS+ Third 10g JHFS+ Fourth 10g with different file formats then the ones shown above), I now get this error when clicking continue from bootcamp:

The startup disk cannot be partitioned or restored to a single partition

The startup disk must be formatted as a single Mac OS Extended Journaled volume or already partitioned by Boot Camp Assistant for installing Windows.

I cannot seem to get past this step. Does anyone know how I can install Windows 10 without BootCamp due to this error? I already have the Windows 10 ISO file.

I do not want to have to reformat my computer again (I know that is the easy way around this issue). I want to work my way through this issue.

You can simply click past the error, but when you try to install windows, you'll get an error that it's in the wrong partition style. You can create the bootable USB drive, it's just telling you that you won't be able to install windows unless you decide to do that.

The latest Windows 10 ISO file (October Update) is over 4GB in size, so you have to partition the USB drive to exFAT on Mac before burning. If not, you will receive waring message in Boot Camp Assistant.

Actually, there are a few good ISO burner apps (Ether, UUbyte, DiskMarkX) out there than Boot Camp, which does good in creating dual boot on Mac. If the Windows 10 bootable USB will be used somewhere else, just skip Boot Camp.