Samsung galaxy s2 running on android version 5.1.1 lollipop (root & gapps bugs)

I newly installed the latest lollipop rom in my Samsung galaxy s2 gt-i9100 after the installation developer option to enable root is no where to be found, I tried flashing the gapps but it refuses to flash with the cyanogen recovery.. then I tried installing back the KitKat recovery to flash the gapps still yet it refuses... now I'm unable to flash anything with the cyanogen recovery..

pls folks how can I get rid of this two ptoblems/bugs?