[obvious]n00b[/obvious]

I was referred to Zen Cart by a friend in the CentOS community. I'm looking for an ecommerce solution and have been for the better part of four days. At this point I'm on information overload so hopefully I won't get any RTFM responses (which I probably deserve).

Questions I couldn't find answers to:

1. I do not want to assume that the latest download of 1.3.8a is a fully patched release. Anyone care to confirm or deny this?
2. I have a need for third party sales which I'm unsure if they can be handled in Zen Cart. (cart runs on site "A" and sells products for developer "B" and developer "C". Developer B and C need to produce product activation and receive payment directly. Developer B and C are two different entities with similar payment gateway ie PayPal but different payment email addresses.) Possible or already done?
3. I would also like to know if the system does by default or with module secure digital downloads either by unique links or otherwise.
4. Optional. Anyone had any experience in offering / supplying activation codes for digital media. Gun for hire?

Thanks for taking the time to read or respond.

Sam