Liver and kidney cysts are, in most cases, benign.
I believe that you are doing all you can in terms of follow-up. In fact, I cannot recommend any more comprehensive tests.
A liver biopsy indeed would be the next diagnostic step, and if negative, would make liver disease less likely.
The same goes for the kidney cyst. A sizable number of the general population have kidney cysts, and do so without any added risk.
Periodic followup, with serial imaging studies for instance, is recommended to ensure the size, shape and character of the cysts don't change.
This can be discussed with your personal physician.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin Pho, M.D.
www.kevinmd.com
www.twitter.com/kevinmd