Sure. That's what Pro Import is for. Check the help. If you have specific questions come back.
You subject goes from AE to FCP but your question goes from FCP to AE.
Moving the timeline from FCPX to AE is done with Myl's advice. (Whatever happend to Automatic Duck?)
Going from AE to FCPX is not possible, AFAIK, without rendering.
> (Whatever happend to Automatic Duck?)
Adobe acquired the software from Automatic Duck and hired Wes and Harry Plate. The Pro Import After Effects feature in After Effects is the updated Pro Import AE functionality previously sold by Automatic Duck.
BTW, you can download other Automatic Duck software from their website for free these days.
I remember now, it's all coming back to me.