FamilyPacks

Our familypack-based service is almost ready to go, but a few questions remain. 
The service a Basic and Premium service, with an option to upgrade from Basic to Premium. 
Do all members of the package have to upgrade individually or only the plan manager?
If we allow multiple subscriptions per user, can the plan manager subscribe to single service type only, or a mix of Basic and Premium could be possible?

I assume by family packs you mean CBSubs Family Plans integration? Upgrades do not upgrade the shared subscriptions. They will have to re-share the new upgraded plan.

If we allow multiple subscriptions per user, can the plan manager subscribe to single service type only, or a mix of Basic and Premium could be possible?

If Basic and Premium aren't marked Exclusive they can subscribe to both at the same time, yes.

Given the limitations (for our model) we are considering the following:

1. Abandon FamilyPack subscriptions.
2. Offer Standard and Premium subscriptions. 
3. Use standard signups (1 per member)
4. Allow multiple subscriptions per user, so one person (parent) can pay for, and manage all subscriptions. 
5. I am assuming each subscription can be upgraded independently, by the parent subscriber. 

Although this is not a FamilyPack, but I am hoping we can provide similar functionality via this setup.

[Questions]
Can a users select number of subscriptions when signing up?
Can each subscription be upgraded independently?
If a user signs up for several subscriptions can the same email address be used for all subscriptions, or unique email addresses will necessary?
We also want to mandatory identify verification via Stripe & CB Verify. Please provide directions to implement this feature. 

Given the limitations (for our model) we are considering the following:

I'm not sure why you'd do this. You can't have a user pay for another user. The only way to safely share a subscription is CBSubs Family Plans. Otherwise if you've a situation where they're just buying multiple "licenses" or "seats" you'd use CBSubs Options for that so the price can dynamically changed based off that number.

What limitation of CBSubs Family Plans is the problem for you? We're open to suggestions here and if it's simple enough often can be implemented in as little as a day.

Can a users select number of subscriptions when signing up?

When allowing multiple subscriptions to a plan? No.

Can each subscription be upgraded independently?

It's complicated. I believe the multi-subscription per plan functionality somewhat breaks upgrade processes and is primarily meant to be used for plans marked non-exclusive, which don't upgrade.

If a user signs up for several subscriptions can the same email address be used for all subscriptions, or unique email addresses will necessary?

If you're making new accounts no they can't use the same email address. Joomla requires email address to be unique.

We also want to mandatory identify verification via Stripe & CB Verify. Please provide directions to implement this feature.

Simply install CB ID Verify, configure your API settings (instructions are provided inside the plugin with links), and specify where you want it to id verify. That's all you'll need to do.

The limitation to upgrade FamilyPack is the issue. You mentioned that upgrades do not upgrade the shared subscriptions. They will have to re-share the new upgraded plan. So, I was looking for another option.

[desired scenario]
We offer FamilyPack of 5 users, for Standard and Premium subscriptions.
FamilyPack owner can add users to the pack via CBSubs via a subscription that will increase value of a 'max_users' field.
FamilyPack owner can upgrade a Standard subscription.
The upgrade will assign all users in FamilyPack to new Premium user group.

Upgrading of shared family plans is something I can explore implementing if that's the only limitation. It might not be too difficult to implement as long as both plans have family share enabled. Basically it'd need to transfer the shared subscriptions from 1 plan to another.