The ideal opening for a 30" x 80" barn door would be 26" x 78".
We do not recommend cutting or trimming track or hardware in any way. This would void the warranty.
For this door you would need a minimum of 90" ceiling height.
If you're using the mounting board that comes with the kit, there will be approximately 1.25" of space between the wall and the door. If you require more space you will just need to use a thicker mounting board.
Yes, the hardware kit comes with stoppers that are installed on the track where you would like the door to stop at.
The mounting board is 0.5" x 4.5" x 80".
Each 32" door slab would require it's own track. A single 78-3/4" is not enough for both doors to share and be able to open fully. Also, we do not offer slabs only on HomeDepot.com.
This door will work for the opening that you described.
That could certainly be done if desired.
The track is not able to be cut down, it is pre-drilled for installation. Cutting it down would also void the warranty. Unfortunately we do not offer a shorter track either.