If you breed your albino lab to your granite you will have all triple het offspring:
if you holdback a pair of those and breed them to each other (sib to sib) you have a small chance of getting your triple visual as Harald has stated.
as for the inbreeding aspect: if you do not add new blood to the line you run the risk of having problems. I personally would not go more than one generation of a sib to sib breeding but that would be in the abundance of caution. This was what I was told by another breeder a few years back.
There is also a "snakebytestv" episode about this that may be worth checking out:
http://www.youtube.com/watch?v=Wzg1zic-zQU
I would also be interested to hear what the consensus on inbreeding is, just to have more info available.