I have just figured out a few things about the Tantive shoot-out, I will put this together to show this in video form at some point but I feel I have finally cracked open the possibilities of getting this opening chronologically correct sequentially.

Here is the report.

As mentioned before previously missing Splice between Star Destroyer and Tantive exterior Explosion.
From the exterior explosion we cut straight to the second version of 3P0 & R2-D2 in the corridor and straight to the dialogue about “they shot down the main reactor”
The troops Running are moved to after this dialogue about the main reactor rather than before. Joining up with them taking their positions at the airlock.
The shot of the airlock troops from the second corridor shootout is moved and flipped to the first shootout and comes before anyone else get’s shot.
Instead of the dissolve we see the 3 Rebel troops running (From first corridor battle) and being shot at in the
next corridor as retreating and segway into the corridor with 3P0 and R2-D2
Replacing the Flipped (and now moved in the timeline) shot of the troops from the airlock corridor we insert the shot at the end of the sequence of the 2 troops who run and turn and fire which lines up with the Storm trooper being hit. But it is spliced at the point at which the trooper fires.
Some left overs of the 2 Rebel troops firing are used at the end after 3P0 and R2-D2 make it across the corridor and the storm troopers turning the corner firing.

The start of the shot of the troops turning the corner firing might be an alternate take or cut away for the Rebel Trooper shot in front of 3P0 & R2-D2

It is finally solved!

Conclusion = Too much footage used and placed in the wrong order. And if there was not “Too much footage” used it would never be fixable like Empire Strikes Back Cloud City Shoot out so for this I am very grateful 😃