Docile geese: American, Sebastapol.
All geese are loud, very loud piercing sound. Don't get them if you have close neighbors.
You can't separate them once they've bonded, like you could with chickens or ducks. So once a pair has imprinted/bonded, you can't try and make them breed with others, it won't work. They will just scream and honk for weeks, even if they aren't allowed to see each other.
Keep them in pairs or even-numbered flocks.
Their poop doesn't smell bad when they're eating grass. It only stinks when they eat pellets.
They can live for decades, so be sure you're commited. Do you really want a bird that will be around 20+ years?