Customer groups: register forms, activation, restrict prods

We have a Magento store which requires some customisation to meet our needs: 1) We need three customer registration pages (students, naturopaths, general public) - with different fields for each customer group. Each form must send an email with all entered data to our admin email address. When someone goes to register they will be presented with a page listing the different types of customer group, click on a link relating to their customer group and then they will be displayed the relevant registration form. 2) When 2 of the customer groups register, they will need to be activated by an admin before being given access to login/purchase from the store. We have tested an existing extension on Magento connect which provides all of the functionality we want and would be happy to have this extension implemented. See [login to view URL] If possible, one customer group will not require activation - if this is too difficult we would be open to making activation neccessary for all customer groups. Please provide your opinion on this. 3) We need to restrict the general public (whether they have registered or not) from being able to purchase certain categories of products. This could be done in two ways. Our preference would be that a general public user (registered or not) would only be able to see the Add to cart button on certain categories of products. Instead they would see a message telling them that they must be registered/logged in as a student/naturopath to purchase these types of products. The second way would be to prevent people from purchasing without registering, hiding the ability to add an item to the cart without registering. A message would indicate to users that they need to register before gaining access to add items to their cart/purchase items. Then using an extension ([login to view URL]) to prevent access to certain categories based on customer group. Please provide your opinion on this. Thanks a lot.