Hi. Just to chime in as a modeler...

If you want to keep that body mass, you should seriously think about increasing the size of the neck to match. You can slide on the head depending on how realistic you want to be. One thing you didn't seem to take into account when using your ref is that the orc is actually average sized to thin. The rest of his bulk comes from his armor. So, if you're going for something similar, you may want to tone his mass down a little. Just a thought.