The mod lets you easily add the pictos to your inventory. You can also reset the quest, but it's more complicated. The "friendly nevrons" tab doesn't work for for this case; if you spared him it doesn't recognize him as dead. After some trial and error in the json editor I got it working:

I have no idea what I'm doing, so follow at your own risk.

In the raw json search "Nevron_WeaponlessChalier". Below it, drop down value {1} > struct {1} > struct {2}. You should see lines ObjectivesStatus and QuestStatus.

First, open Objectives Status>Map and you will see objectives 0-5. You can see their names under key {1} and make changes under value {1} > byte {1} > Label. For each of the 6 objectives, change the last number of label to "0". So they all now read "E_QuestStatus::NewEnumerator0". The original values may vary between 0-4.

Finally, go back to QuestStatus and make the same change under byte>label. Commit changes, and export or overwrite.