User Relationships support

Sure, write a bridge module.

That's not Subscriptions' job.

I know that Subscriptions is too complex for some people, and apparently you know it, too, yet you are requesting to add more complexity to support an obscure* third-party module? Do you see the contradiction?

Not useful at all from my point of view, IMHO.

You are welcome to use or not use Subscriptions, as you prefer. :-)

*) Not obscure in the general sense, only as far as Subscriptions is concerned, because I cannot remember any other such request for that module in my five years of maintaining Subscriptions.

I have tried to simply setup an auto-subscription to get an email every time a node is created and edited without taking account if the user is friend or not and without giving the user to opt to share or not the creation/edition with others and I even got your module to work. I never receive a single email even pushing the email immediately.

I don't even understand what's the difference between it and Notifications because both talk about subscriptions. So confusing.

Clearly, you need more support than we can give you, for free and for pay. Sorry.

Let's leave it at #2:

Note: Subscription has the most awful UI of all the Drupal modules I have worked with, it's just impossible to configure and make it work, it's all guessing. Not useful at all from my point of view, IMHO.