Looking for general best practices to extend functionality

Hello everyone,
I've just downloaded and installed Sitefinity and I'm starting to develop my first site.  There are a few things I need to accomplish that I don't think are possible out of the box.  Can someone point me in the right direction as to how I would accomplish the following:

First, I need to provide the CMS users with the ability to add products and manufacturers.  The manufacturers should have names and addresses, and the names should appear in a dropdown when adding products.  I'm assuming I would create these as custom modules, but please confirm that this would be the approach.  Also, should both products and manufacturers be created this way?  Is it possible to populate a dropdown in the products module with the manufacturers?

I'd also like to be able to assign articles to a magazine issue.  The issue should also have other properties such as a link to a digital edition, etc.  Would this need to be created in the same way as products, or would I take a different approach?

Is it possible to display an entire list of content based on category?  I see how you can add a list of news, list of videos, etc., but is there a way to provide a list of all content assigned to a category, regardless of what content type it is?  For example, when a user goes to a page on the front end, I'd like to show the top x number of content items in a particular category.  It could be articles, video, products, etc.

Finally, is there an easy way to provide a list of most popular (viewed) content?

I appreciate any and all help.  I understand that there is plenty of documentation out there for me to accomplish these things, I just need general direction in the approach I should take and what I should be searching for.

Hello Ryan,

 On the custom modules question - the implementation that you described is one possible approach. An easier one, however, would be to use our Taxonomies module and create either custom Taxonomies or directly create categories/tags and assign them to the module items that you need. For the products/manufacturers case, for example, you can have a Products module and a Manufacturers Taxonomy. Then you will be able to assign different manufacturers from your taxonomy to the product Items.
The filtering through category is absolutely possible (and you can assign categories to whatever Content items you want). How the Categories widget should be configured can be found in this page of our documentation:
http://www.sitefinity.com/documentation/documentationarticles/user-guide/widgets/classifications-widgets-group/configuring-the-categories-widget 
As for the most viewed content - all of these statistics can be set and followed through our Analytics module. More information on it you can read here:
http://www.sitefinity.com/documentation/documentationarticles/user-guide/sitefinity-analytics 

Thank you for the information, Svetoslav.  I think I have most of the direction I need.  However, I do have a couple of follow up questions.

I'm not sure that custom Taxonomies will fit my needs for manufacturers, but please correct me if I'm wrong.  In addition to the manufacturer name, I need to store, display, and provide the ability to filter and sort by additional properties such as address, city, state, zip, etc.

Finally, as far as the most viewed content, is there any way you can tap into some sort of API for that to display a list on the front-end website?

Thanks,
Ryan

Hi Ryan,

 If you want to store more data about the manufacturers, then you will have to develop two different modules (as taxonomies can hold only one value). 
On the Analytics - this is just the google-provided functionality and we do not persist it in our database. This means that if you want to display the information on another page, you can directly use the google API to do it (and this is actually what we are doing in the Analytics module, as well).