There is little evidence of behavioral modernity - cave paintings, Venus figurines, hearths, burials etc. prior to 50,000 years ago. There is some evidence so the time could always be pushed back.
Farmers compete for land. Migratory hunter-gatherers are just passing through, so there is less competition for land. Also, bands usually mate with nearby bands, who are often more distant relatives.
There has not been much evidence of hunter-gatherer bands clashing violently then or even in modern times, including observations over past centuries. There is a plethora of evidence of post-neolithic farming and then industrial societies being this way.