>Any suggestions on how to populate these controls with the first available selection upon entry into the form and when a parent control changes? TIA

Got Mere Mortals? If so, the framework has a concession for this with bizobj's. Checkout the section in the Developers Guide on "Requerying List Boxes and Combo Boxes". This is somewhere in the BizObj stuff, like around page 88 and does a good job of explaining the VFP101 aspect to.