Hey miycko I'll try my best to help. But I wont be brutal.
studies from life
The boxes are pretty close.
Having a good guess- I'd say it looks like the top metal box is cube like. Try making a diagonal from corner to corner on all the sides. Its seems to go back in space further than in width. So possibly that ones off. It will help put the inner box in the centre too.
Number 1 is correct. Number 2 is fairly good but further on is bit off. Just practice making diagonals with your boxes corner to corner same as studies from life. So you can repeat the same size box further back.
stuff referenced from photos
I'm not too sure. Worth a look at darker pencils and line weight for things with depth.
I cant say, Im not very good at figures myself. I havent gotten into the fighting games but love some of the first person shooters. Isaac clarke would be awesome, try that one!