How do I power user manage my photo library effectively?

Ok, I have the following situation:

A large amount of photos on my iPhone taking up a third of the memory (phone is getting full).

Up until now, I synced my Photostream to my Macbook Pro to backup my photos. The shortage of free memory has revealed some underlying issues with my backup and general handling of my photo library.

Some questions/issues:

Edited photos are not syncing to my Macbook, 'only' originals, and if I delete photos on my iPhone to free up space, my edited photos are gone.

Solution:

Buy an iCloud backup upgrade for a month, activate the full iCloud media sync in Photos and have all the edits sync to my Macbook.

Issue 1: Since I have already imported 6+ months of photos via the Photostream sync function, will it mess up my library and create duplicates of photos, or are the photos that already are in my library left out of the full iCloud library sync?

Issue 2: Will photos that are no longer on my iPhone, but have already been synced to my Macbook (via the iPhones Photostream) get synced to my iPhone to fill it up even more (which would counter my plan to sync the (edited) photos to my Macbook not sync past photos to my iPhone (low space).

Issue 3: After the library has synced and I have all edited photos on my Macbook and then delete some on my iPhone, will they get deleted on the Macbook as well?

Remember: the goal is to backup edited photos (which Photostream backup doesn't), and then to delete two thirds of the photos (not all of them are edited) on my iPhone to free up space, but to keep them on my Macbook.

Any thoughts/hints concerning all of this?

As a side note: I have been struggling to get a good working method in regard to my local photo organization going, and I feel the Mac Photos app doesn't cut it.

Can someone suggest a robust method of backing up iPhone photos to local drives that doesn't involve jumping through too many hoops? Should I switch to Lightroom for local photo organizing and editing? Manually connecting the iPhone to the Macbook and import all new photos every two weeks or so?

I guess I have to say goodbye to editing photos in the iOS photos app at the least. I thought about 'exporting' edited photos from the iOS app to a shared album and then importing those edits on my Macbook from the shared album to my photo library, but this involves some work.

Could anyone recommend a good method/app/workflow for this task?

Much appreciated!

PS: Should I rather be posting this question to the iCloud subforum?