I'm using danny branch and  a custom bsp to create an overo image. My goal is to add these features: a root custom password, autologin with root and rootfs read only. I have some issues with IMAGE_FEATURES:

If you add tools-sdk it doesn't work unless you also inherit core-image (it would be useful a comment about this in local.conf)
Once I inherit core-image,

password: if I add debug-tweaks, I get a blank passwd, Ok. If I don't add it, I get an unknown passwd (tried blank, gumstix, root, overo...)
          I think the problem is at the end of core-image.bbclass, when we zap the pass. If I change
zap_root_password () {
- sed 's%^root:[^:]*:%root:*:%' < ${IMAGE_ROOTFS}/etc/passwd >${IMAGE_ROOTFS}/etc/passwd.new
+ sed 's%^root:[^:]*:%root::%' < ${IMAGE_ROOTFS}/etc/passwd >${IMAGE_ROOTFS}/etc/passwd.new
mv ${IMAGE_ROOTFS}/etc/passwd.new ${IMAGE_ROOTFS}/etc/passwd
          It leaves the passwd blank even if debug-tweaks is not added.   

autologin:  image.bbclass has a 
set_image_autologin () {
        sed -i 's%^AUTOLOGIN=\"false"%AUTOLOGIN="true"%g' ${IMAGE_ROOTFS}/etc/sysconfig/gpelogin
but it doesn't work. Not surprised here as there is no sysconfig in the system or gpelogin. 
I've tried http://gallinazo.flightgear.org/software/setting-up-autologin-on-a-gumstix/ but there is not "/etc/autologin.profile" either and it didn't work.

rootfs read only: I've tried adding the read_only_rootfs_hook () function included in Yocto 1.4 but it didn't work (no errors).

Can anyone give me advice on how to achieve these 3 things? Even knowing what files I need to change in the rootfs would help me a lot, I can create the functions and call ROOTFS_POSTPROCESS_COMMAND myself.