Jhiaxus > Sideswipe -> Electro
Jhiaxus > Sideswipe -> Electro----- Optimus Prime
Jhiaxus > Sideswipe -> Electro -> Optimus Prime -> Eagle Eye
...which is the last of the G2 Transformer names starting with E and there are no G2 TFs whose name starts with a Y, so in the interest of keeping this game going, we'll default back to the next available letter which is L.
liege maximo
Jhiaxus > Sideswipe -> Electro -> Optimus Prime -> Eagle Eye -> Liege Maximo -> Onslaught
Jhiaxus > Sideswipe -> Electro -> Optimus Prime -> Eagle Eye -> Liege Maximo -> Onslaught> Tracks
Jhiaxus > Sideswipe -> Electro -> Optimus Prime -> Eagle Eye -> Liege Maximo -> Onslaught> Tracks -> Skydive