Okay, so I'm going to put aside the cost and randomness problems and just answer this as: Which ability would you most want your Estates to have?
Bailey, by a country mile.
Not only will it not take up space, but being able to chain that many Knight attacks together will absolutely annihilate the other guy's deck.
Molly and Destry would be a distant second and third, respectively, useful only if there's no other villages or draw, again respectively.
It's hard to see why Natalie would be a good idea. You don't normally want your deck full of weak terminal gainers. I guess it's a neat interaction with Gardens or Silk Road: Not only can you get more Estates, but there would have to be cost reduction so you'd also be able to get Gardens and Silk Roads with your Natalies. So that niche use would put Natalie in fourth place.
The others are absolute garbage things to inherit, only good for screwing around in Lord Rattington games.