Let me try to answer your questions.
collections created within the Lr Mobile app will be automatically synced to the back-end. You can add photos manually from your camera roll or enable a collection for "Auto Add". With that all future camera shots will be automatically imported to Lr Mobile and synced
correct. changes will be synced from Lr Mobile to Lr Desktop - back&forth
3) local camera roll deletion is not connected to the Cloud back-end. But be carefull that the import/sync is finished before you trigger that.
as answerd before. the cloud back-end is not connected to the device camera roll
video is not supported yet
original resolution images will be downloaded to Lr Desktop. Preview images will be shown in the Lr Web view Adobe Lightroom
when you create a collection within Lr Desktop and add your photos you would like to sync, then you can enable this collection for sync. As soon your are signed-in and start the sync (via the top left activity panel) you will notice a little checkbox beside the collection. When you check this sync start to run. Lr Deskop generates smart previews and uploads these to the back-end (plus thumbnail previews + meta-data). When you open up Lr Mobile app and you would like to make an edit, the Lr Mobile app loads the smart preview form the back-end and syncs back the meta-data or edit setting.
Hope that helps you to start.
Thanks Guido, some quick points of clarification...
1) Are the photos loaded from the phone at original resolution or are they downgraded? Does the LR app need to be open?
4) When I delete from LR on the Phone it does not appear to be deleting from LR on the desktop -- should it be or do I need to delete from each device?
6) When I export an image from Lightroom Desktop that has been synced from LR mobile to CC, will it be at the original resolution or is it compromised in some way?
8) How do I enable the syncing with my existing collection?
1) Lr Mobile keeps the original resolution. You don't need to have Lr Desktop running while doing the import on the phone. When you would like to have access your originals you need to open Lr Desktop. At the moment Lr Desktop is holding all the originals.
When you delete a photo from a collection on the phone, the photo is just removed from the collection in Lr Desktop but still in your catalog
6) Lr Desktop has always access to the original and you can define the export output as you want
8) Start the sync via the top left activity panel and enable this little checkbox beside your collection. With the exception that Smart Collection are not yet supported.
Hope that helps