Interesting that you don’t mention what I find to be the #1 cause of plantar fascitis. It is trigger points in the soleus muscle which cannot be stretched in the same manner that is used to stretch the other calf muscle (the gastrocnemius). You can work the foot and heeel all day long and not resolve the problem until you get rid of the triggr points in the soleus and learn how to stretch it properly.
I am a massage therapist and you don’t even mention seeing this group of professionals who can be very helpful in working with someone. Massage the calf; do NOT massage the foot. Once you have gotten rid of the trigger points and gotten the calf muscles in good shape you can then massage the foot…..but chances are you wont’ need to. It will have become a non-issue.