The Faceplate Bevel: Using a Carpet Cutting Device (it has a small blade mounted at a 45 degree angle) I was able to slice an angled cut into the foam, beveling it nicely. Since the blade on this device is so short, I had to use the exactoknife to to the actual beveling.
I lined up the blade with the pointed corner, and made sure it was in the pre-sliced groove made by the carpet cutter. Then I just sawed through the foam, and hoped for the best.

At times, the cut dipped down, but that can be patched later with glue/latex Foam and a plaster trowel to even out the appearance.

The Keypad: I measured out/cut a 6 1/2" x 6 1/2" square from the rest of the extra foam I had.
I did a 1 1/2" bevel around this square using the same method described above.
I cut a 4" tall x 3" wide rectangle right through piece. I then flipped the block so I was carving at it from the back, and removed an extra 1/2".
This makes it like a picture frame.
I cut another rectangle ( 4 1/2 wide x 2 1/2 tall ) and steeply beveled the edges.

Now, I glued the keypad frame and the decorative beveled rectangle to the main face plate. It was left overnight for the glue to solidify.

General Face plate cutting: I held the face plate on, monitor poking through, to the frame, and made some trimmings here and there.

By shoving the Diskdrive (on an LC series machine, you can have the diskdrive mounted slightly forward - beyond where its casing would end) into the foam face plate, it makes an impression of how large you need to cut the foam. I cut down 1" and a bit into the foam. The only space where I actually cut all the way through was where the floppy disk would emerge. Again, the same method I used with the Keypad. I ended up making a sort of "picture frame" effect.

In this case, it allowed the diskdrive to extend 1" into the foam at the same time, allowing the LC 475 to be flush with the faceplates inside.

I drew the 'ventilation holes' of the terminal on to the foam using a gel-pen (they are great, since they don't require the ball to roll to have the ink come out, like in a Bic pen). As I drew them on, the tip of the gel pen acted like a small blade, piercing the upper later of foam. This was great, and I just used the tip of the exacto knife to finish removing the unwanted foam. After some careful cutting, the result looks great.