It took me longer to grasp than it should have, but I'm pretty sure R5-SK1 is a nod to Skippy, the Jedi Droid.  If you don't know what that is, you missed Star Wars Tales - and that was a fine comic.  This new droid is one of four figures in a new Disney parks exclusive droid pack for Rogue One, where one droid looks like one you probably have, another is coming with a big vehicle later, and the remaining two are seemingly brand new for this set.   If you like droids, this is a good week to be you - we're going to examine the entire set.  Read on!