Hi Sharon! Any of the machines are good for piecing...as for FM? You want to get one that you don't have to actually remove the feed dogs everytime that you want to FMQ...the 201-2 that I just got yesterday you can drop the feed dogs on, but it's a process more than just "flipping a switch".
Other than that, I'm really not sure if there's a treadle that you can drop the dogs on...will have to research it!