Best Situation for do Merge and assemble Steps

Dear all,

I would like to do the InSAR processing for the whole of S1 scene for three earthquakes have happened with an hour difference time. At first, I would like to know whether I can assemble the following S1 images with this coverage or not?

Secondly, two S1 images, before and after earthquakes, have not complete coverage as follows. To do the merge step, should I do it after making the interferograms?

Best regards,