The EACCES error is a bit easier to fix. You most likely have some messed up permissions after running node / bower etc as sudo. First thing you need to do is blow away the node_modules folder and rebuild it.
Check out these instructions: Npm Debugging Guidelines (Failed npm install, bower install, or gulp build? Read this)
Specifically, read Austin’s comment too: Npm Debugging Guidelines (Failed npm install, bower install, or gulp build? Read this)
Generally speaking, you shouldn’t need to run anything as sudo in order to build Sage themes - if you do, then you need to figure out the reasons why your server demands it, and correct that accordingly. If you run npm or bower as sudo it will lead to tears.