Hi,
I am not an artist. I think that you would be best off getting the basic female form sketched
out without all of the roboty bits first. I think you are on the right track using the female side
and front sketches. The trick will be to get the proportions and measurements right. Once you
have the correct basic shape, THEN start to add the robot bits using your Maria picture, overlaid
and at the same scale.
The principle will be the same as modelling a three view aircraft. Get the basic shapes first and
then use lofts to fill in the details.

Three things about your file.
There are two yellow warnings in the timeline. Always fix these AS SOON AS THEY HAPPEN.
Your sketches are not all fully defined. I know splines are difficult to constrain and you might
get away with that but they are not impossible to constrain.
With splines - less is more. I think you have maybe three or four too many spline points. I might
be wrong on that one.
I would try to get the body right first to the shoulders. Forget the neck for now. Also forget the
girl bits on front (have to be careful not to use prohibited language on the forum 😎 ) for now.
The arms and legs will be modelled similar to Armour pieces with mechanical joints. The head will
be similar to a helmet.
Overall it will be a challenge but I think you are on the right track. Do not rely on complex sketches.
Remember that you can use the sculpting tools. Use simple sketches to create various cutting tools.
Also remember that the real Maria was a person in a robot costume so callibrate your Maria picture
so that it is the same scale as your female form. It will make modifying the basic form easier when
you get up to that bit. Your head is right but the knees and feet are wrong. Hips are just a little out.

Good challenge, I might add it to my own practice list.
Cheers
Andrew