I was wondering if someone can assistance with my design and verify that this will work and if anyone has any pointers. This design will service users in 3 different domains one of which is a separate forest. There is a full two way trust between the two forest's. Will be installing SCCM 2012 SP1. I apologize for such a large picture. I wanted to make sure it could be seen.

The WAN speeds and forests/domains are missing in your graphic.

You should place and internet facing MP (https) in the DMZ.
Using an MP and SUP for 25 users is overkill.