Firstly the tutorial is not limited to btrfs, I tried it first but had little success so I switched to ext4 and am close to getting it exactly as desired.
Second you can't use exfat as it isn't a linux filesystem and therefore do not support partitions, so you can only use linux filesystems for the purpose of the tutorial.
Lastly, you can use Ext2 windows application that is available on sourceforge to mount linux filesystems and access them on windows as if they were fat filesystems, works flawlessly with ext4, haven't tried btrfs yet. Alternatively you can use total commander plugin DiskInternal Reader to access linux filesystems on windows, the shortcoming here is that they will be mounted as read-only unlike Ext2 app that gives you full read and write access.
Hope it was informative enough for you.