Alan, I wish we had good answers to your questions.  One I can answer:  According to the label there are no grazing restrictions following application of Milestone, so I think you would be ok with using your lamb or other grazing animals.  (The herbicide can actually be concentrated as it passes thru the animal because the animal is not absorbing it).  The label states that sensitive crops should not be planted for a year after application.  It does not seem to break down much in a compost pile, but if the soil is warm and moist, soil organisms will help break down the chemical.  I would dig up soil in one of the more affected areas late this fall or early next spring, bring it inside and plant beans in it to see how they do.  If they grow ok, it should be broken down sufficiently.  

I cannot comment on the safety of your vegetables, because this herbicide has not been tested for safety on them, so we have no basis for determining whether the vegetables are safe or not.