You don't really need Decree if you manage to get a 39 out and attach it with either Lightning Blade or Tornado Bringer. I also think you don't have enough monsters that summon other monsters from the deck, like GK Spy does, thus I'd stick with a 20/20 ratio. I believe Unicorn is the best of the ZW cards. I run two so give it a try. I have yet to use Ultimate Shield's eff, but it works great for Abyss Dweller and I rarely worry about Dimensional Prison or BTH. I don't see how Backup Warrior would work with Estelle when she already has 4 other level 5s that are more reliable and Trag. I almost forgot. two 39s and one c39 are perfect if you're using PoA.
The reason I run decree is because I'm afraid of bottomless and solemns. Even compulsory when they use it on the summon before I can equip it on
And the thing about running a second monk. Idk since I have very less spells. Might add it when I make a 20/20 version of the deck.
And I'll test it without back up warrior. I run it cuz I have this friend who's a pro deck builder and it worked well for him.
1. Summon monk discard spell for Estelle in def
2. Back up warrior gets summoned, than xyz for some rank 5
I guess its very conditional to summon him
If you have 2 free slots in your Extra Deck:
You can try to switch both "The Tricky" with 2 "Instant Fusion"s. Then add 1 Level 4 and 1 Level 5 Fusion monster that can be Special Summoned via Instant Fusion. Sure you have to pay 1000 LP, but Instant Fusion will give you flexibility between Rank 4/5, you don't have to discard, and didn't take your Normal Summon (You will want to Normal Summon Estelle Drawn).