How to Transfer or Merge Data/Information from One Apple Account to Another

I need some help on a fairly limited number of questions.

My daughter passed away a few weeks back.  She owned 5 i-devices:  Four iPads (recent) and one iPhone (7 or 8).  I am court-appointed executor of her estate.

The good news is that I know the passcodes to three of the iPads.  I also know her Apple ID and password, so I also have access to her iCloud contents and account information.  The result is I have easy access to her mail (this has been invaluable in paying her bills) and photos (3,000 plus, mostly of my

grandchildren).

The bad news is that I have run out of tries on the phone and final iPad.  I assume that these are now useless and should be recycled or destroyed.  They would contain all her text messages (she did not back up to iCloud) and will presumably be gone forever.  I doubt that these will be useful in any event.

What is the simplest way to (a) preserve her photos and (b) transfer her Apple account to me?  Two of the iPads are used by her kids (now my responsibility), and I would like not to have to wipe their iPads clean of all the games they have downloaded.

Since I have all the necessary passwords and passcodes, I am hoping this is not a complicated legal dance.

Any guidance or strategy you can offer would be deeply appreciated.  For what it’s worth, I am an experienced Apple user (my Mac Plus still works!).  I’ve browsed the knowledge base articles, but all seem to deal with people who don’t know IDs, passcodes or passwords.