New to WordPress but not AWS

Hello Everyone,

I want to start off by saying that I have done a lot of searching and testing before I turned to asking here. Like the title reads, I am new to WordPress. I am a certified AWS Solutions Architect, CCNA, and have years of experience with Python and less with a handful of other scripting languages. I love networking and security! However, when it comes to content creation and graphic design I fall hopelessly short. Anyways, I have a lot of SMB clients who I support and I recently decided I would try my hand at building a hosting company. I found wpmudev and WordPress Multi Site and became very excited. Unfortunately, I am hitting some road blocks and before I start spending a lot of time trying to reinvent the wheel I thought I would ask here.

Most of my clients host blogs or other types of informative sites. The vast majority of their content is large graphics. A few of them also have extremely large catalogs. My focus over the past few days has been on cache, DB performance, and CDN. I have everything worked out, more or less, except the CDN.

I have purchased a number of plugins to help me streamline the setup. I was settled on W3 Total Cache. It seemed to do everything I needed it to until I got to setting up the CDN. I wanted to be able to use S3 for my content storage, because there will be A LOT, and deliver that via Cloud Front. This works wonderfully for the main domain but once I start adding new sites it all breaks down. I mapped the domains to the sub-directories but I can't get any of the subs to work.

I am open to suggestions. I'd like to try and solve this with plugins but if I can't I will try to build a solution. Before I put the time in to do that I thought I would ask people who know a lot more about this than I do.

Thank you!