Assistance with animation/VFX on a movie project

[dark_apprentice]

Hello to everyone, I hope that i didn't go to the wrong topics sorry if so. As some of you around here may already know since April 2016 I am working on a new kind of project, that is not related with music/bands/recording other bands etc. and it's about a Fan movie of my own personal Star Wars story. The story takes places after Return Of The Jedi and before The Force Awakens you can read more right here. However due to my new job I managed to start couple of months ago and the minimum time I have after that for the music projects or anything else I still make a small progress, that is not yet to show (I have few teaser WIPs, but still figuring out what to include and what not, since most of the stuff I am doing on my own as I wanted to). Problem is that I will need assistance from times to times from someone who is more experienced than me in animations and VFX. Speaking of this the animations that I can use so far are with Blender, 3Ds Max, Cinema 4D. Lately and mostly around my girlfriend I have learned for some other amazing "magic boxes", such as the Unlreal Enginge, CryEngine, Unity3D.

My thoughts at this moment are:

* If possible, could a certain animation from Unlreal Enginge (for example) can be used for another scene in the movie, of course by using a green screen.
- A space flight with the Falcon flying by near some planet. 
- Adding vehicles/ships that are not in the original filmed scene. Like the actor is walking in a forest during winter and it's needed to see few AT-AT's following him with TIE Fighters above?

* Or creating a certain element of a building/room/ that can be used for realistic background during a raw footage of the actor/actors standing/walking on the green screen.

 

[dark_apprentice]

Is it possible to use animation made with Cryengine or Unreal Engine and a movie scene that is shot with green screen