Hey there @katje-katrien ,
Thank you for getting in touch and reporting these issues to us!
The matter regarding the 'Plant a Tree DLC' tile is known to the team and shouldn't affect any players from actually being able to access the Ceiba Tree in Eden Burning.
Regarding the 'Reset Scenario' button still appearing, I've passed this onto the team.
Regarding your issues with the scenario rewards, have you completely re-played the scenario again and found they still haven't unlocked or have you been using the same save?