This deck all about X costs in cards, and Hydras happen to be the best Magic creatures in these colors for X
Jozu helps shift the field presence in your favor, and if you use a cost-reduction card, you can remove a high-cost carry from play, putting your opponent behind on the field
Another possible combo is with Capsize, following the same Buyback logic as Searing Touch, but this costs 1 generic and 2 Blue with Buyback 3, so it can only return a handful of permanents to their owners' hands
Gitrog isn't afraid to dance on the knife's edge and get rid of your most valuable game pieces---including the very lands that allow you to cast spells at all---in exchange for completely different pieces
However, since it's an FF-limited build, I think it's fine
A creature with Protection from a quality, let's say a colour for simplicity, can't be targeted by spells and abilities of that colour (like Shroud, that's regardless of who controls them)