1 - Yes, products can trigger the creation of user accounts and the adding of the user into one or more user groups. The user groups can then be used with permissions to control access to concrete5 pages.

2 - This isn't really to do with community store, this is really a question of how you want to serve the videos. There are pros and cons of different streaming approaches (and I'm not an expert here):

- YouTube - free and easy, and you can make videos unlisted so that they aren't accidentally discovered. It's also easy to embed them on a site using the built in block. The con here is that people can still get to the youtube video link and share that, so you'd only use this if it wasn't something you were _too_ worried about
- Vimeo - also very easy to upload and embed, handles things like different bitrates for mobiles as well. You can then set video to only allow playing if the video is embedded on a particular domain, so you can create a decent level of protection. The con is that you need their Plus or Pro account to do that protection, which has a yearly cost.
- Hosting on Amazon S3. There is a way to set up an S3 bucket to host videos in a way where the website has to generate a key to access them. That key has an expiry on it and the only way to generate it is via the concrete5 website. We've done this on a site and it works quite well, but it requires both some fiddly coding to set up the whole key generation step, as well as configuration on Amazon. You also have to do all the video encoding yourself. The pro of this is that it's pretty cheap to host large files and stream.
- Locally hosted - I don't think there's a way to protect files this way from being directly accessed, and bandwidth/size can be a problem.

So my recommendation would be to investigate a Vimeo account. The yearly cost is worth it to save the hassle of the initial set up and doing all the encoding. We've used this ourselves on a project with solid results.

3 - Recurring subscriptions are quite a different thing from traditional transactions, and aren't really covered by Community Store. Recurring transactions require the set up of plans, the management of accounts, reminder emails, expired credit card notifications and updating, the actual automated billing process and a whole bunch of management features. Each payment gateway handles this differently too, with Stripe being one of more well known to handle subscriptions.. but it's not just a case of enabling a few options, it's a major exercise to code this up - and then different subscription systems have different rules as well. I'd argue there are more differences with a traditional shop than there are similarties.

So my recommendation would be to avoid the use of recurring billing if possible. You could set up user groups to automatically expire users from a group, and you could play around with permissions and groups to create a system that prompts people to renew _after_ their subscription has expired.

You could have the main landing page for logged in users (like a members area home) have some blocks on it that are conditional on the user groups. If someone is a paid member they see all the content they have purchased. If they login and view that area, but they are no longer in the group there can be some blocks that conditionally appear based on this that say 'hey, it looks like you are no longer a member', and then present a particular renew membership product to purchase and buy.