First of all the two machines take different formats. You might want to consider purchasing Embird that will convert the two formats so that you can use the same design with each machine sans the Disney designs that are propietary to Brother and can't be used on any other machine.

You are correct that you will need a reader writer box for the Brother machine because your machines are different formats. The PED basic sounds like a good plan (available on line at Walmart for around $139.).

I have two different brand machines and also found that the hoops are not interchangeable either. The only things that may be interchageable are feet and needles. The bobbins may be different so you really have to watch which bobbin you have and don't get them mixed up.

I would thoroughly read the Brother manual before purchasing anything further...they are pretty good about documetation and educating if you practice the manual page by painful page.