I just got the Unicorn with 4604 stars, spending about 60 gems mainly speeding up breeding whenever one of my two nest hatches. Mining helped too as I got 3 stars per bomb more than 3 times.
On top of getting the Unicorn when I tranfered Capt.K9 from den to nest, the next re-breed of Pandaffodil+Rock Rhino gave a 16hr timer, which is likely Wagrid.
Wow, haven't had such luck in breeding limiteds before this.
As the last community decor is too far to reach I have left my Evolution flower empty until K9 hatches.
Good luck to all who are within reach of the Unicorn, 4hr 38 min left.