Leo's sketch had the only visual reference to the free floating "nodes" of Guardian mode. It's the glowing thing on his cross band. All the turtles were to wear a node on their stealth outfit at some point but only Leo's got the "experimental" alternate color.
I remember a gimmick I designed involving Raph's Sai and a grapling device on his arm guards. I no longer have the design but I think it was reused in a later episode of Back to the sewers. If you look at the sai an extra blade is prominently shown with the same color as the main blade
I got lazy with Mikey's Chucks. I defaulted to an earlier design I used in the TMNT Fast Forward season. I figured I'd think of something cooler later. I did redesign a totally new "holster" for Mikey's chucks.
I tagged each design with the "Shinobi" designation just to have a new mode for Guardian mode. To my knowledge these designs were never really utilised for use by the turtles. Production drew inspiration from Leo's Shinobi Design when they did a Foot clan stealth design for Back to the sewers.
Again, the colors on these came out real cool!