Tbh, I think most people wouldn't mind if you used an NPC to appraise and gave the exp to Liana. (Or even made the exp go poof)
Like... Rather than carrying about the appraisal rewards, I think most people only care for having reports appraised in the first place. I mean, I have been kinda lazy to appraise them recently myself, and not because I didn't want the rewards, but just because I was feeling lazy.
So uhn... If you'd be willing to help with Appraisals by using Heljikka or whichever NPC you'd prefer, I'd say it is all fine.