1. Can a type of user have access based on group membership (for example) to a range of profiles? E.g. user1 has paid subscription and can review/access a range of other profiles (user2, 3, 4 etc).
It is possible, but it is extremely complicated to setup. We have a tutorial for "family" subscriptions usage below, but I do not recommend it unless you're familiar with CB, CBSubs, and SQL.
www.joomlapolis.com/documentation/283-cb-paid-subscriptions/tutorials/18405-family-plan-membership-part-1
There is no official functionality at this time for 1 user to purchase subscriptions for other users.
2. Can user2 opt out of being included in group/search based on criteria
That would be entirely up to you in regards to modifying the above usage. It maybe better to just generate coupon codes that the purchasing user can give to others for 100% discount. Tutorial for that as follows (also very complex requiring SQL experience).
www.joomlapolis.com/documentation/283-cb-paid-subscriptions/tutorials/18407-purchasing-discount-coupons
3. Can access to profiles/groups/records be restricted by subscription criteria ?
Yes, you can protect tabs, fields, or entire profiles using subscriptions in CBSubs.
Are the any specific issues with having template build considered over the CB add-on versions? We are looking for a quite elegant / cool design which I think will need external development.
CB has a template system for CB it self and most of its plugins can also individually have their own templates. As long as you maintain your templates when new features are added to that specific template file it should be fine. However, CB it self and its plugins are Bootstrap 3 powered so it could be just as simple as turning off CBs Bootstrap and loading in your own if you want to restyle everything at once.
krileon
) so hopefully they can help us evaluate to the next level.