Free limited plan with pro sites

Hi !

I'm launching a new SAAS and I have a few questions about pro sites.

I want two different plans :
1. Starter Pack
2. Gold Pack

By default, user will have 14 days on Gold Pack them downgrade to Starter Pack if they don't pay.

Starter Pack specifications :
- Limit the number of custom post types (different limits depending on custom post types)
- Access a limited amount of themes

Gold Pack specifications :
- Some plugins may be activated automatically only for them but they don't have to access the "plugins" page, it has to be totally transparent.
- They can do everything they want !

I know I can give the 14 free days on Gold Pack easily.

For the rest :
1. I have to create two levels, Starter and Gold, right ? Or can I use the default free pro sites level ?
2. Can I restrict the themes that are available in Starter or Gold Pack ?
3. With posts & quotas module, I can choose the number of posts. But can I specify different quotas for custom post types ?
4. Can I activate plugins automatically only for them but they can not access the "plugins" page, which should be totally transparent ?

Thanks for your time !