Please note that the same zone number in different locations can vary widely, soils may be very different; so Ventura, California (zone 10) and the other zones mentioned by posters in the above thread may have really different results from you when trying Fuyu Persimmons and the suggested guild companions.
What kind of trees do you want to base a guild on that already seem to grow well in your area? What soil type(s) will your guilds be growing in and what are the climate extremes (temperatures in summer & winter, winds, etc.) that your plants will need to survive and even thrive?
I don't know your experience level, so excuse me if this is repeated information for you:
There are some basic concepts of what kinds of plants you'll want to surround your tree with: insectaries to attract beneficial insects/birds) / mulch plants (to "chop & drop" the leaves in place around the tree) / nitrogen fixers (clovers, beans, etc. to reduce the need for fertlizers) / nutrient accumulators (I believe there is some controversy as to whether dynamic nutrient accumulators like yarrow, dandelion, chicory, etc. actually let the plants around them benefit from the minerals the accumulator plants "bring up" from the subsoil; but I plant them in my guilds for increased plant diversity if nothing else.) / grass suppressing bulbs planted in a circle at the expected full-grown drip line of your tree (spring bulbs that die back by early summer so they won't compete with your tree during the summer--active growing period.).
Research is great and helps stack the odds in your favor; but nothing beats the feeling of starting to actually grow a tree and experimenting with the guild to see what mix actually works together for you on your particular site. Hope this helps...and good luck!