Mackey was a SC engineer officer attached to Price's army. I suspect he was just passing along a rumor he heard. He had no evident motive to spin a tale. and I'm not clear how the tale makes the parties look any better.

The escape is/was inexplicable. Arch Dobbins' brigade is the unit usually said to have been occupying the escape path. Dobbins' men were mostly raw recruits, and Dobbins had operated as a semi-guerilla in Eastern AR in 1863-64 rather than as a part of the regular Confederate army.

Still, Dobbins had a decent reputation as an officer. His regimental commanders had seen some service. And, it's hard to believe any widow in the area had enough food stocked to feed an entire brigade.

What I suspect happened is that the brigade higher officers, but not the men or the lower level officers, did indeed sup at a house. And that the men, inexperienced, didn't do a good job patrolling. Or else mistook the retreating Union troops for friendly forces. After all, Price's army was a grab bag of men with many different uniforms (including captured Union blue), and in the post assault confusion and darkness, with many of Price's units moving around, a sentry could have let slip the sign-countersign to a southern-accented Union soldier.