Though his family owned slaves, General James Longstreet might be an interesting figure for you to look at. He was not an avid supporter of secession, though he ultimately joined and fought for the CSA. After the war, is where he is most interesting. Longstreet joined the Republican Party (where he was the highest ranking Confederate during Reconstruction) urged reconciliation, endorsed Grant for president, acknowledged the rights of freed slaved to vote, equal rights and so forth. Here is a well sourced and recognized thesis from Loyola University in New Orleans (where Longstreet lived) that argues that Longstreet's reputation as a general and a person was severely damaged in the Lost Cause mythology for these actions. He was seen as a traitor to the South for becoming a Republican.
There may have been, but looking at what happened to General Cleburne may be illustrative of what happens. After the disastrous defeat at Chattanooga in late 1863 he proposed to his fellow officers that we allow slaves to fight for their freedom. The idea was met with silence, and when word leaked to Richmond about he was blackballed from higher command, despite being the best divisional commander in the west.
Official Records, Series I, vol. 52, Part 2, pp. 586–92.