Read a Doujin and got an idea [transformation]

[Dojo_dude]

I remember reading this Doujin awhile back, where a large monster 'fished' with the female adventurers. Using some magic the monster turned them into 'onaholes', it was so wild that I never forgot about it! XD

The Doujin in question FYI was "Studio TAGATA (Yontarou) Dluminia Oukoku Monogatari Tsurie".

How could this made into a quest mod? Using Racemenu, one could change the characters skin and Amputator Framework to shrink [which is how it works] the limbs to 0.
On the other hand, Cursed Loot does have a growing Rubber Suit quest? I still have to fix some mod compatibilty issues before I can even start on making this one.

[Icarian Dreams]

IMO absolutely doable, using exactly the methods you mentioned. The only issues I see is a) SexLab not having great animation packs for amputees, and b) having all four limbs removed pretty much makes the game unplayable. Though I guess for the latter, it could be reversible and happen just for the sake of the quest - similar as in the doujin, in fact.