I don't have an answer to that.l I do not use the cloud backup and I have a bundle with Fios so I don't have a limit on my data. Maybe @bestcee Courtney knows.
No, it doesn't use your internet. You download the software to your computer and it runs just like it did before the cloud existed. I can use LR and PS without even being logged in to my Adobe account.
Yep, no data required, except to run the check to make sure you paid. I'm monthly, so once a month it checks.
I use Serif's Craft Artist. But it's not supported anymore and is starting to struggle with current operating systems. Prior to that I used Serif's desktop publisher Pageplus. So I'm going to beta test their new desktop publisher Affinity Publisher, and see if that is good for scrapping with or not.
I'm still using the, uh, "vintage" PS CS2. I'll make the leap to CC when CS2 is finally no longer compatible with anything I want to use.
I purchased the Photography PS CC a while back - when my Mac died I tried to use other free programs, but after using PS for so long the free programs just caused frustration.