To answer your first question, the regulated voltage goes into here (it distributes the power across all the "sensors", or in my case the servos):
https://drive.google.com/file/d/1vaxRtpy-8PR3IuKpRexzVN-yO3i8sLRY/view?usp=sharing
Secondly, the mega is connected like always (one end of the cord in mega, other end in my mac. no adapter unless i'm understanding you wrong):
Third, the socket works fine. I was powering my nodemcu earlier. You know, "deauthorizing" wifi and such 
And lastly, i'm using the new shield, not the one that got it's traces cut
https://drive.google.com/file/d/1piTOx6UY_cGwnGt5UMvcHjtFKDmCmDLz/view?usp=sharing
again, i'm 90% certain it's not the wiring. when i started on this i was completely clueless arduino wise, and kept it really simple. Also, sorry about the links, i couldn't figure out how to get a link to put in the insert image when the picture is from my downloads