Just jumping in on this. Our last trip to WDW was June 2015. We have red, blue, purple, and green mug lids and handles. We now have 5 with us. Color coding was great for us knowing who's mug was whose... especially when refilling when tired early or very late. We are going again over Thanksgiving. From what I gather, we have different color lids, but still only 4 different colors....but also no corresponding color on the actual mug portion to match? 
Secondly, we are on the DP but going via split stay. My understanding is that once activated the mugs are good for 14 days. However, instead of getting 3 sets of 5 mugs each do we simply forfeit getting the mugs for stays 2 and 3 or is there any way to credit that back anyhow?
Finally, while the colors may have changed, is the actual picture different from 2015 (pictures in OP)?
Thanks!