Here is what I think happened. You gave two names of databases: Photos Library.photoslibrary and iPhoto Library.migratedphotolibrary. The first was your current library, which was messed up. The second was the iPhoto library that was migrated to Photos when you moved from iPhoto to Photos in an OS upgrade. It had been renamed with the "migrated" added. I was hoping that the iPhoto library had most of your older photos in it that you could recover, then import the newer ones from your iPhone after it was sorted out. That is what you now have, and it works (you can edit as you wanted to, so the database is not corrupted now). At this point you need to get the more recent photos from your phones to that database. To do that, connect the phones to the Mac, then run Photos. In the sidebar you should see your iPhone. Select that and wait. It will read the phone and show thumbnails of all of the images there. There should be a dividing line showing which images Photos already has and which ones it doesn't, which it will call New. Once it is done (it could take a while with that many images), in the upper right corner is a box labelled "Import all New Items." Clicking that will do just that, import all images on the phone that are NOT in the library into the library and that are showing in the New Images section. Or you can browse through the images and select them one by one, or in bunches with the SHIFT key and import them manually.
The name of your database can be anything you want, as long as you are pointing to it with Photos/Preferences, which is why it works with iPhotos as the first section.
Once you have all your images into one database, you can then decide what to do with all the extras. Frankly, being cautious, I would save them on an external drive for a few months or until I was certain I didn't need them, I had everything I wanted or needed.
OR, IF, and that is a big IF, all the images you want are on the phone, you could create a new database from scratch, then import all of those images and be done with it.
And a final option is that if the smaller photos database (11.71GB) has all the newer images in full size, you could open Photos, change the database to that one, select all the new images, export them to files, then change the database to the iPhotos database name, look for the exported files and import them into the newer database.
It's up to you.