Hi, Christopher Neigeborn. Could you provide some more details about why you believe that adding them to an IMDb name list is not possible for you? Mind you, the list has to be a name list.
IMDb lists can only contain items that are of uniform kinds (just like arrays in medium-level programming languages); so IMDb name lists only contain item references to IMDb name (nm) entries, IMDb title lists only contain item references to IMDb title (tt) entries and IMDb image lists only contain item references to IMDb images (rm), for examples.
Christopher: Because these people both work in the Adult genre, their names will not be found by the regular method of adding names to lists. However, you can add them to a list by entering their IMDb name constant as found in the URLs of their pages. For example, Kayden Kross's URL is https://www.imdb.com/name/nm2628347/, so you can add her to a list by entering nm2628347.
Jeorj Euler