Is it possible to remap the keys in the function row?
1.1.2. What Ukelele can’t do
Ukelele is not intended for remapping modifier keys. For example, it is not intended for
swapping the command and option keys. Mac OS X 10.4 introduced some flexibility in rearranging
the modifier keys. Otherwise, other software, such as Better Touch Tool (https://www.boastr.net/), Karabiner (formerly KeyRemap4MacBook) (https://pqrs.org/osx/karabiner/)
or DoubleCommand (http://doublecommand.sourceforge.net/), can do this and more.
…(snip)…
Mapping the F-keys (F1 through F19) does not work with a keyboard layout, so Ukelele prevents you doing this.