Using A Reference Video Track in UE4's Sequencer


I am participating in a 48-Hour film project and am using Unreal to simulate a VFX shot where a person flings a ball far into the air. I wanted to import the video of the person flinging their hands, and use it as a reference in the sequencer so I can match the 3D ball’s movements, then create a composite video of the shot by exporting the sequencer shot of the ball with a solid colored background, keying out the background in After Effects, and then layering the ball shot on top of the live action video. I have the animation part covered, but is there any way to import the video into the sequencer timeline and layer it under the ball VFX shot?

Thanks so much,