Also, a 3d modeler isn't doing advanced programming. I doubt much resources were affected by modelers modeling. At least there is variety, which is also important.
It takes a lot of time to do, it's digital sculpture after all, getting the proportion right is never fast and involves a lot of iterations.
And it involves many other department in the pipeline like rigging for armatures systems with bones specific for each model and animations which are dependent from the Armature. Make a different armature, make a new animation set.
Making a digital model is not the hardest thing in the world to do.
The parts that make the process long is the conceptual stage and approvals especially if the product is a licence I.P. The approval stage on that level is pretty much where developers get stuck for a bit. But what the character, item, or location ultimately looks like is approved at the conceptual stage and if an I.P is involved it's going to involve the I.P holders. The model may have some tweaks after seeing it in a 3D space, but this isn't nearly as time consuming as a physical piece.
The male and female Predator very likely share the same armature. I don't know why they wouldn't the models are not so radically different that it seems like it would.
Of course it's not the hardest, I'll even say veteran finds it easy.
But it's never the fastest either.
And of course you can't get stuck at modeling because at that point you start leaving Pre-Prod and have to move on.
I'm pretty sure it's not a displacement map doing the changes, which mean each model had to be weight painted.
(Still waiting for an automation one day to actually work without having to do manually. I know it's likely a dream but who knows !)
I'm pretty sure you know what I talk about and how "fast and fun" the process is.
I've also rarely seen animations retarget works correctly everytime without involving some manual adjustment.
That's precious time for a character having hundreds of animations.