This really is out of scope for this forum. Please keep in mind Farseer is not about drawing anything and the samples we provide are not part of the physics engine. The samples main goal is to show off all of Farseer features. As a nice side effect they
provide one or two methods of drawing physical objects. That is however not a supported part of Farseer Physics and the drawing code is subject to change on very short notice, so it is probably nothing you want to base your own game on. It is ok for prototyping
but nothing more.
One goal in the examples for instance is to somewhat show the user what is going on in Farseer internally by visualizing joint interactions etc. In a real game you probably want to hide as much of the internal physics stuff as possible to make things look
Your drawing code should be highly dependent on your actual game and we can't provide support for every possible solution out there. It will look quite different for example whether you do a lot of sprite based drawing or use 3D models for a 2.5D
Farseer 3.2 used a material system, which was easy to use for us but unfortunately heightened the impression that Farseer and the drawing system were somewhat two parts of the same engine and tightly coupled. Therefore it was replaced with spritebatch based
drawing where possible in 3.3. That results in a lot more rendering code, which hopefully is easier to understand and follow for people just starting with Farseer and XNA.
That said: Drawing breakable bodies is fairly complex and will require quite some effort. And as with all drawing you will need to keep track of which texture/primitives/objects/etc... you would like to have attached to which Fixture for yourself.
The same applies to your body removal problem: Bodies and graphical representations are decoupled and therefore you have to get rid of any graphical objects for yourself. You can however use a bodies/fixtures UserData pointer to point to any object you like...
for instance your sprite/texture/class... so when you destroy a body somewhere in your code, just remember to destroy the object the UserData points to first in proper way and you should be fine.