Poor Louise ... she steps out for a church service and journalists suddenly take notice of her.
It seems to me that Edward & Sophie have pretty firmly established that their children won't be part of the working RF by giving them non-royal titles and keeping them out of the limelight. Articles by newspapers speculating about their future roles is ... speculation to sell papers/get clicks.
Just like with Beatrice and Eugenie I see no reason why Louise or James shouldn't carry out engagements.
If they want...though like in Sweden they should be paid by engagement. This way they could still lead a normal life and support causes they may find interesting.