I've worked as a Bell Local Tutor and researched these questions for the Cambridge Delta FAQ
on this site.
You've basically got it right, apart from:
- They aren't the only providers who do online or blended courses - I'm going through the list on the Cambridge ESOL site at the moment and of the ones who still offer Delta courses (the list is really out of date), about half offer these options (the other options being intensive ten or so weeks face to face or part time face to face over nine months)
- The peer observations are a Cambridge requirement, so with Bell you will need to arrange for them yourself (or perhaps that is included if you do the optional face to face component with Bell)
- In reality it is your responsibility to find a suitable Local Tutor, and Bell don't give a lot of help for this
As you said, the Local Tutor issue is the main one - do you have a suitable person to do it?