Converting 2D picture to 3D model and then changing metrics

I am converting a 2D image of an animal to a 3D model (I was thinking of making an .svg file and then uploading that to Blender) however the image must be to scale (I have measurements from a dataset, I have attached an image showing where the measurements have been taken). After the image is converted I want to model individual animals based on the dataset of measurements (i.e. changing height of the dorsal fin, length of the flippers, etc.). What do you all think is the most effective way to do all of this. The main objective is to get different surface area and volume measurements from each individual, so the images do not need to look realistic or aesthetically pleasing, but they do need to be accurate.

make a quick basemesh then sculpt it, then retopo it.

just enter the image as a background image

then adjust the scale to be real in blender like 1 meter - 1 meter on the image background
in N panel at bottom for image background

then just model it in 3D

but you would need like 3 images minimum
Side top and front view
but could need other sides too if not symmetrical

happy bl