Q. Can we create a site from a blank site template and then upgrade to other templates?
A. You can have functionality available in other site templates in a site created through the Blank Site template by activating the required features. However you cannot have the functionality of the Meeting Site template in a Blank Site template.
Q. Can different types of list types be nested? For example, can a picture list be hosted as a folder in a document list?
A. No, you cannot nest different types of list. However, you can create your own list definitions by inheriting from the existing ones and modify the behavior as required.