.STL Files in Blender to be used for an animation. Should I recreate them in blender? Here is a scene I'm using as a reference.
https://ibb.co/n9Yub8 
Here a portion of a trailer assembly not fully finished using for reference to show what i mean.
https://ibb.co/d3r0io 
One of the trailers alone has 673,475 tris / 269,538 faces / 428,851 verts,
and its not even fully finished yet its about 25% complete and there will be from 4-6 of them in the scene alone not including everything else.
Here is how the frame looks like in edit mode.
https://ibb.co/hapWpT 

So before i continue should i just recreate everything in blender or is there a way to reduce the amount of vertices?
I just don't want to waste time placing everything and my computer giving up.

I've used the edge split modifier with the smooth shading tool, limited dissolve, remove doubles.
I do not think there is easy way, start by removing doubles link,then check all other technics in the link, start cleaning it manually, then it is more time management. If you think that  cleaning it manual is more time consuming tha building it, build it.