Should I Skip Recovery Installation Step From CyanogenMod ROM
You can check whether you're susceptible by installing this app - Exynos Mem Bug Checker.

Next - installing a custom kernel isn't all that difficult and neither is it too risky if you know what you're doing.

For the S2 - Siyah kernel and Dorimanx kernel are the two most popular ones. However, the latest kernels are meant for Android 4.2.x and higher. So, use the correct version for your OS. Should you decide to install a custom ROM like CyanogenMod or Paranoid Android etc., it will install a kernel with a recovery too (as an example - Siyah and Dorimanx - which is based on Siyah - have a touch based recovery, so you can scroll through the options by touch instead of repeatedly clicking the volume buttons to scroll as in CyanogenMod or others).

The CF-Root kernel that you installed to root the S2 is a modified stock kernel, IIRC. Therefore, it might be susceptible to the Superbrick / eMMC bug.