In Yocto, a meta-efl layer is provided by the meta-openembedded layer. It contains EFL, Elementary, Enlightenment, Terminology and other recipes.

So, the first step is to add this layer in conf/bblayer.conf:

  ${TOPDIR}/src/meta-openembedded/meta-efl \

Next, to install Enlightenment and Terminology, add the following lines to your recipe:

#add enlightenment window manager
IMAGE_INSTALL += "terminology"

If you just want Elementary and EFL, just add the lines below or something that depends on EFL or Elementary:

IMAGE_INSTALL += "elementary-tests"