Yeah I've always thought Fidd deserves a huge visual update, like Sion level, but still maintaining his identity in that he's a scarecrow, and he's made of sticks. It's just I think he needs to look like a more menacing scarecrow, with more scary-looking sticks that are jagged and weirdly shaped, or even having 'sticks' that are much more reinforced by using dozens and dozens of them. I think his visual update should be as big of a change as the difference between Scarecrow in Arkham Asylum and Scarecrow in Arkham Knight
Anywho, in regards to how he could be related to Fiddle, maybe he was his first creation? When he was a young, ignorant little kid, maybe he inadvertently created Fiddle by desiring to witness something really 'scary-looking', though he didn't realize it would develop a mind of its own? I think it would also explain why he says 'yes, master' when you select him. He's not saying it to the player, he's saying it to the champion that created him, feigning being on his side, biding his time, waiting for the moment to destroy his master.