I think the easiest way would be to make a mesh body suit with the transparent effects then just, turn on all the plphas for the underlying body.
What I am not sure of, which is probaboy the core of your question, is can you apply a texture with transparency on a mesh object.
I want to say I tried once, to add "cuts" to a one piece bathing suit template mesh, but it didn't work, but that may also (and likely) me doing something wrong.
Also, I fid a search for jelly avatar, slime girl avatar, and similar, which feels like it would bepopular enough tonexist, and none ofnthe results look like they have a "transparent effect".
The closest thing I can think of are cum systems, which I am pretty sure work by having "mesh drops and tendrals". And not through transparrnt textures on a large "sheet" mesh.
That said, you couls, possibly use one of these tonget a sort of Jelly effect maybe by using a full alpha Avatar base, then turning on all of the fluids layers to max, and tinting it (which is an option on INM).
Probably not the most ideal way, and you would have to find a way to lock it "maxed" because in the case of INM, Linden water would remove it all.
It alsonwould be more of a "slime monster/person" effect than a "jelly/jello" look.
