I somewhat agree they just become that generation's Juvia / purple hair lady.
Although I don't mind Yui, Marin and Violet staying loyal to their initial antagonists, but still open to share upon their request, but only confined to the 3 or 4 people who were involved in the plot which is:
Juvia/Purple lady should just be secondary and stick to the village's cumdump IMO, or tempts MC.
I might even speculate to convince the chief to finally join them, it will have to him giving in to Yui/Marin/Violet..or an all out.
On another note, I do agree with the general sentiment that Yui x Dukall's virginity scene is a little disappointing; maybe it would have been a bit better if the scenes were reversed?
Either way it looks like the physical corruptions done and now its just to corrupt their mind fully now, looking forward to the next releases.