Edit 2 videos simultaneously?

I'm editing 360 video - which I edit both a flat version and a 360 version. Right now I edit the flat version and go back and do the same edits on the 360 version.  Is there any way to do them simultaneously, so if I trim one clip it does the identical trim on the other?  

No, there isn't any way to do them simultaneously, but you could finish the flat version and copy/paste everything into a new 360 timeline.

How would I copy and paste the edits to a new timeline (new project?)

Finish your flat edit, then make a new 360 project.

Re-open the flat edit, select all (command + A), copy (command + C), go back to the new empty 360 project and paste (command + V).

If there are graphics, overlays, photos, or other non-equirectangular elements, you'll need to decide where and how those appear in the 360 sphere.

I made my flat trims and copied and pasted everything into a new 360 project.  It copied the actual flat clip with trims.  How do I replace it with my 360 video?  I tried dragging to replace but then it wiped out the trimming.  

I'm not sure I understand what you're asking here.

Did you use the 360 footage to make the 'flat' edits? What are the timeline specs for the flat edits?

Did you paste into a 360 timeline?

More information is needed here. If you cut 360 clips into, for instance, a flat 1080 timeline, you tag that footage as 360 and then reframe it in the 1080 timeline. If you then copy that 360 clip from the 1080 timeline and paste it into a 360 timeline, it should show as equirectangular in that 360 timeline.

Maybe I'll start over in case I wasn't explaining properly.
I recorded a video in 360 (5.7k).  I than did 2 exports from insta360 studio - a 5.7k 360 one and a 1440p reframed flat one.  
I then made a 1440p flat project and do all my edits.  Now I want those identical edit on my 360 video.  Basically I want to copy/paste my edits - not the actual clips.  Basically I'm trying to avoid having do do all my edits twice.    

Oh, sorry. That explains a lot!
I thought you were cutting the flat version with the 360 files, and would recommend doing so for future 360 projects. Or, if it's possible, make a Multicam clip with both sets of files and just swap angles for a given timeline, but again would have to happen prior to edit.