Queen Louise's mother, Princess Charlotte of Denmark. She had a flair for politics, and tried to have Hesse-Kassel elevated to a kingdom in the renounciation negotions, but failed.
The negotiations about renouncing their claims to the Danish throne in the 1850s? (Or the claims to the Hessian throne in the 1860/70s? Though it wouldn't make much sense to try to elevate something you were about to renounce.)
Anyway, this must mean that the family had some contact with the court in Kassel. Kmerov, you seem incredibly knowledgable about the Danish royals, do you know what kind of relationship Queen Louise's family had with the electoral court and especially the morganatic spouses like the Princess of Hanau and Horowitz? Eric Lowe wrote that Queen Louise was quite accepting of her Hessian relatives with their morganatic family arrangements.
Yes, the negotiations about the danish throne. The Hesse family was under pressure by virtually everyone to give up the Danish throne.
The family did have contacts with the court in Kassel. As head of the family the Elector had to give consent to marriages and such, also Louises and her siblings. Louises family was also heirs to the electorial throne so her father and brother made visits to the court from time to time.
I don't know if Louise had personal contact with the Elector or his wife while in Rumpenheim or Cassel. The marriage of Friedrich Wilhelm I and his morganatic wife was not popular in Hesse-Cassel or outside.
In Denmark the royal women did not accept Countess Danner, so they only met with Frederik VII when he was alone without his wife, but I don't know if that was the case with the Elector.