Q: How can one sync a) Albums to all my iOS devices and b) Photos

The best way to save and backup all your photos is on your computer.

And every image you are having in your camera roll will be backed up in iCloud or iTunes, if you enable it:

http://support.apple.com/kb/HT1766?viewlocale=en_US&locale=en_US

Do you use a computer with your IOS devices? What kind of computer?

My Qs were more specific

It is easier to answer specific question, when I know whch options you are having on your computers. I.e. I wondered if you would be able to use Shared PhotoStreams  instead of My Photo Stream, but that would require MacOS X 10.9. at least, see: iCloud: Using and troubleshooting Shared Photo Streams

( pls see above): 1/ I was assuming that via iCloud only " my Photostream" is distributed onto all aktivated iOs- devices;

The Photostream "My Photo Stream" uses a buffer in iCloud: Each device will upload the most recent (last month)  photos saved to the Camera Roll, if Photo Stream is enabled and any photo you share to the stream. The buffer in iCloud will only keep the photos for a month - it is meant as a streaming buffer and not as a storage. And the stream you are seeing on your devices is fed from this buffer. Depending on when you activate Photo Stream on the devices they will show different selections of photos - it depends on what is currently in iCloud. With IOS 7.0.4 you could also stream to Shared Streams, and they will keep all photos in iCloud, only you would need to upgrade.

- having said so: does iCloud then back up my Camera Roll ( Photos)  in toto ?

Your Photostream is generated automatically from all photos saved to your camera roll, so if you keep all photos in your camera roll and save any new photos from the Photo Stream to your camera roll, they will all be backed up, inclding any videos in your camera roll. This list describes in detail, what automatically will be backed up in iCloud over Wi-Fi:

See: iCloud: Backup and restore overview

2/ the 2nd Q posed was: Is there a mechanism to save/ backup on the Album level ( I guessed it can be done via iTunes), but also through iCloud (??)

That is exactly, why I asked for your system versions: if you could create Shared Streams, you could use 100 separate streams just like albums, and all would be stored in iCloud.

But there is no way to structure "My Photo Stream".

But the iCloud backup of your devices will include all application data, so albums you define in the Photos app will also be included, only not the photos synced to your device using iTunes, unless you save them to the camera roll.

- Does one then HAVE TO make b/u via iTunes for EACH iOs device ( and of course the whole Library file

You can make your iCloud backup using Wi-Fi ( iCloud: Backup and restore overview), but you will have more control over it, when you create the backup using iTunes. And syncing using USB is faster than Wi-Fi.

4/ Does one have to save (B/U) as well via iTunes into the iPhoto library,

as also via iCloud (?)

It is recommended: the iCloud backup of your IOS devices will enable you to restore your devices directly from iCloud, but a separate backup in iTunes will make it possible to restore a new replacement device from the backup, if your iPad, iPhone will be stolen, lost, or defective. And you can access the iTunes backup even when the network is down, or there is a problem with your iCloud account.

iPhoto library: When you automatically import the photoStream into your iPhoto library on your Mac, any backup of your iPhoto library will be a backup of your Photo Stream photos as well. I'd create the albums in iPhoto on your Mac.

Some Links: 

iCloud: My Photo Stream troubleshooting

iCloud: Photo Stream FAQ

Regards

Léonie

A remark about Photostream : its deletion logic for pics, once 1000 is reached is intransparent

This is explaine d by the fact that "my Photo Stream" is not meant to be a storage, just a transient buffer. You have one month time to grab your photos from the stream, and then they will be removed, consider it to be a stream of photos that you are viewing from a narrow window. You are supposed to download the photos to your camera roll or to an event on your mac, as soon as you are seein it in the stream. After a month it will be gone.

I'm hesitant that my current iPhone4 is too underpowered to run iOs7 without hickups

For what it's worth I had iOS 7 running on an iPhone 4 for several months without a problem until I got an 5s iPhone.

Happy New Year

You are welcome

- I realized, that most importantly, first to upgrade to iOs7 ( my new iPhone5s will be running with iOs 7.04;

will come mid Jan); I'm hesitant that my current iPhone4 is too underpowered to run iOs7 without hickups

All reports are saying that iPhone 4 is working well with IOS 7, just like Old Toad confirmed.  It will be much more trouble to have different IOS versions on your devices. You will have to keep and save two versions of each app and they may be behaving differently, some IOS 6 versions will no longer be available after February next year. All in all having all your devices compatible will have many advantages.

a) I like the concept of shared streams ( ~ Albums), BUT:  with whom / where to do I use shared streaming;

understood for each Album  1 stream

You can share with friends and family, or simply with yourself. You can have up to 100 streams. You can set them up on one of your IOS 7 devices - one stream for any album you would create.

Invite yourself to view the shared Stream,  and it will be stored in iCloud. You can view it on all your Mavericks Macs and can add photos from all your devices.

I use this feature to have my most important albums on all Macs, my iPad, my iPod, my iPhone. It is only a selection of photos that I want to have with me and may want as a slideshow. The mediocre photos are tucked away on a mac.

b) the iCloud backup for EACH device will contain Albums for each device (= different ones); also I will NOT sync to a device using iTunes

You have seen the article, what an iCloud backup will save. An iTunes backup will save more, and before restoring your devices I'd always make a full backup in iTunes, but as a routine backup iCloud should suffice.

BUT: only slight disadvantage : Album - Master is the Mac ; I'll keep the iOs - devices' Albums as substructure (??)

I'd use the albums in your Mac's iPhoto library to create the Photo Streams from. You will see both in your iPhoto library - iCloud with the Streams, and your albums and events.

On your iDevices the Shared PhotoStreams will appear as additional shared albums. And you can create more local album that may differ on all devices.

-- Léonie

You are welcome,

and a very "Happy New Year" to you and Old Toad!