Since both Prince Pieter-Christian and Prince Floris didn't seek the Consent to their marriages, they both lost their places in the line of the succession to the Dutch Throne and ceased being members of the Dutch Royal House, same as Prince Johan-Friso (although they are still members of the Dutch Royal Family).
From this point on, however, Prince Friso's situation is completely different. By Royal Decree of 2004, he lost the hereditary title "Prince of Orange-Nassau" by marrying without the Act of Consent. Prince Pieter-Christian and Prince Floris never had the hereditary title to lose it.
Honouring the fact that Prince Johan-Friso was the Sovereign's son, he was granted the hereditary title 'Count of Orange-Nassau", so that his children were not 'commoners'. It was not a demotion; on the contrary, it was an effort to make sure his children are titled in some way.
That is why Prince Johan-Friso's daughters are titled as Luana, Countess of Orange-Nassau, Jonkvrouw van Amsberg and Countess Joanna Zaria of Orange-Nassau, Jonkvrouw van Amsberg. They are both styled/addressed to as "Highborn Lady". Their surname is Van Oranje-Nassau van Amsberg (again, as per Royal Decree of 2004). The titles are hereditary in male lineage.
Prince Johan-Friso is still allowed to used his title 'Prince of Orange-Nassau' as a personal and non-hereditary title, same as Prince Pieter-Christian and Prince Floris, whose title is non-hereditary as well.
The children of Prince Pieter-Christian and Prince Floris, on the other hand, are known Emma van Vollenhoven, Pieter van Vollenhoven (the children of Prince Pieter-Christian) and Magali van Vollenhoven (the daughter of Prince Floris), without any titles or styles.