My custom Shy Guy graphics used in Super Ninji Land and the sequel. The Shy Guys replace Galoombas because I thought they acted similar and the Snifit graphics are for this sprite. I also made graphics for the parachuting Galoomba.
The Shy Guy is used in SP1 and the Snifit + Parachute Shy Guy are SP4. No custom palette should be needed, but I don't recommend using the gray palette (row 9) for the Snifit.