I used to have a few ficus carica bonsai. A lot of my friends now have fig trees from the cuttings. I gave one to friends who bought a farm a few years ago when they put up a green house, planted one in ground, and sold the last two that were being trained as bonsai. I sold everything that had larger leaves since my space is limited.
One year, I had drastically reduced leaf size that lasted all summer. I thought it was something about waking the tree up early to do root work and pruning, but I couldn't replicate the results. I never did anything like defoliation because the trees were still in development.