OK, I'm not familiar with terms, so I'll describe my steps now (yes I have working f22, I needed to run away before breaking something in frustration :D)

I downloaded from here: https://spins.fedoraproject.org/xfce/download/index.html

I used this https://fedoraproject.org/wiki/How_to_create_and_use_Live_USB to do live usb, but I used something like (I can't remember exact order) su -c "livecd-iso-to-disk --format --reset-mbr --home-size-mb 256 Fedora-Workstation-Live-x86_64-28-1.1.iso /dev/sdX"

I think I didn't include --efi, but maybe I did on second try, so it could be

before that with parted or something I managed to make partition bootable

while creating it with that command somewhere in the process it asked for passphrase for something, I didn't remember what, just gave one

And I got login screen with two fields, to enter username, nothing in drop down, and password, and liveuser is not accepted in any combination

I'm now wondering where from you did download your image file and how you made usb? dd?

I mean, so I can repeat your exact steps Since I have suspicion that this part with 'home' made it problem somehow...