Jim, my book "Lee's Tigers" covers this a little bit but I never found any evidence to explain why Lee promoted Gordon over the more senior Hays. My view is it was a combination of things: Gordon's impressive action at the Wilderness, Lee perhaps blaming Hays for the disaster at Rappahannock Station (which really was Lee's fault), and Lee just following his intuition. There's also a good possibility Jubal Early privately recommended Gordon as his replacement (Early had a somewhat contentious history with the Tigers). I do think the 2 Louisiana brigades were consolidated for manpower reasons (they were not the only one) and the consolidated brigade was transferred to Johnson's division to avoid Hays having to serve under Gordon.