I was able to get through the testing phase and got some results and responses from the developers.
In regards to the Skylight issue, there are known issues with the Skylight not receiving indirect light bounces which is why your scenes look so different. This should have been fixed in the most recent release, which occurred today. Try testing in 4.11.2 to see if the issue still occurs.
In regards to the Skeletal Mesh issue, you can only use the Experimental ES3.1 emulation using Metal - the ES2 emulation assumes that bone data will be in uniform buffers but Metal shaders are always ES3.1+ so they use UAV buffers." which may be why the skeletal mesh can’t be seen. Enabling the experimental ES3.1 made the skeletal mesh show back up.
Once the bug (UE-29170) has been fixed and integrated, it will be added the list of known and reported issues for the next upcoming major release or hotfix.
Cheers,