Well after seeing all the life I got on my live rock from floridaliverock.com I would suggest them for live rock. However, getting just 14 lbs of live rock would be costly compared to buying locally.
Just suggesting them for the amount of life you would have on the rocks compared to typical fiji rock and you are setting up a small tank with only shrooms.
Are you going to have a cleanup crew in the tank? If not then if you get a mantis or carnivorous whelk on the rock then it won't matter, they won't have anything to eat except what you feed them.
B.