Very nice! I've done this before on Fedora 23 with OwnCloud, but the procedure was confusing.
I wanted to add something for users who might have an issue like I did. I have a separate physical disk I wanted to setup for the data disk, but found myself running through most of your procedure without having setup or mounted the disk. I took your advice and used the default /var/www/html/nextcloud/data path.
At the NextCloud wizard, I received a "can't read or write into the data directory" message. I knew it had something to do with permissions. First, I had to re-issue the chown apache:apache -R /var/www/html/nextcloud command because once the disk was mounted the data folder reverted back to root:root - that's a given. But the same error came up. So, I figured it was SELINUX and I re-ran the selinux_config.sh script, which gave me an error for each folder saying it was already defined. Even so, I tried NextCloud again and had the same data directory error.
A little poking around and I found this out: you have 2 commands in SELINUX: "semanage fcontext" and "restorecon" ...
The "already defined" error was coming from the semanage fcontext command, so I read a bit about restorecon and discovered that if you add an "-F" parameter, it will force the command rather than bypass it if it's already been run. There is no error from restorecon, it just silently doesn't work. Adding the -F parameter worked: restorecon -R -F ${ocpath}/data.
Thank you, I have a nicely running NextCloud system now!