Based on everything I've heard & read, figs thrive best in base or alkaline soil conditions. So, adding lime is good. Also using a hardwood mulch over a pine based mulch would be better. Not that the hardwood mulch would provide any significant benefits. It's just that the pine might provide negative results in the long run if used extensively. (This doesn't apply to just getting cuttings started. It seems using pine in this way is beneficial in the short term.)

So, do the lemons really offer any secret/special benefits? I doubt there's any special benefit over any other decomposing organic matter - Just my take on it.