kernel-feature-wlan-monitor is the right one, as this will allow both power kernel and cssu thumb community kernel to be supported and not mess up everything (cleven had similar issue). Unless you need some other features in kernel? you can see via e.g. "apt-cache show kernel-power-bootimg", the entry for power51r1 version (type "apt-cache show kernel-power-bootimg | less" and use up/down arrows for easier reading, press "q" to quit) which kernel-feature-'s it does provide and list them as dependency.