Am I candidate for breast fat transfer if I have fibrocystic breast disease, very dense breast tissue, and had a benign lump?

In and of itself, fibrocystic disease should not impact breast augmentation or the outcome of the surgery.  You should continue with annual mammograms for early detection of any breast lumps.

Fat injections to the breast can be successful.  But to get enough volume to have a meaningful result usually requires multiple sessions.  Serial injections can be costly and this fact can make implant augmentation more attractive. 
Mammographic appearance of fat is frequently indistinguishable from normal breast.  The dystrophic calcifications that can occur from fat injections are different in nature from those found in cancer.  Oil cysts from fat also have a distinct appearance.
Thus far the jury is out with regards to cancer detection and fat augmentation.  The data is sparse but I would predict fat demonstrates less obstruction to mammography then implants.  So it is not unreasonable to proceed with fat from that standpoint. 
Fibrocystic disease poses minor technical problems with fat injections but otherwise is not a contraindication.
I hope this helps.