Everything you describe is doable with the following notes:
+ CBSubs supports online and offline payments. So a member can chose to pay online (via Paypal, credit card, etc) or can chose to pay offline (meaning that the member by some other method makes his payment - e.g., personal check sent in email, cash to treasurer, etc). The offline payment must be recorded in CBSubs backend in order for membership to be activated).
+ Cbsubs currently lacks the marketing emails you are requesting. It will send notifications only on triggered events. E.g., if subscription ends and email will be sent to member, administrator etc. At the moment there is not send reminder type email functionality (but it is planned for next release).