I cannot make a determination based on the information provided.  The small spots on the leaves could be caused by a number of different things.  Regardless of the cause, if they are typical of what you are seeing, then I doubt this is responsible for the rapid defoliation.  Certainly they do not resemble any of the symptoms of oak wilt.

Given the seriousness of an oak wilt diagnosis and lack of foliar symptoms, it is important to eliminate other potential causes.  For example, have you used any herbicides in the beds?  How long have the beds been built around these trees?  What are the watering practices?  Live oaks respond badly to "wet feet", so any repeated in the beds might lead to root rot infection by pathogens that like permanently damp soils.  This is particularly hard on live oaks where the root systems have been buried, as in the image.  Beds around live oaks should not be sufficiently deep to bury the flair roots coming off of the base of the trunk.  Note how they look in the woods - they do not have the "telephone pole" appearance at the base as I am seeing in the image..

If we can rule out all other potential causes, then that brings us back to oak wilt.  I recommend you go to the website texasoakwilt.org and read about the disease.  There are also listing of arborists on theat website in your area that can be of service.  Please contact me at <personal data hidden> if you require further assistance.

Dave Appel