I'm not sure I can really answer your question in its entirety, but I'm going to try and offer some input.
I believe that there is very much a role for business analysts in an Agile team. "System
Analyst" is a relatively generic title (since I'm not familiar with your company structure), but I can imagine that the position is similar to a software architect. At any rate, the business analyst position has played a huge role in my previous experiences with companies. However, its important that you understand the true role of your business analyst. In my examples, the business analyst played the role of intermediary, tester, and functional expert. This person would serve as the primary channel of communication between the business resources and the technical resources. He or she would have an extensive operating knowledge of the area of business he/she was assigned to, and would participate in all stages of testing during a project's life-cycle.
But I digress. The systems analyst (architect) serves the role of technical planning and implementation, as well as thorough testing and technical subject matter expert. The business analyst serves in the above-mentioned role, and also serves as the primary planner for the Agile life-cycle (assigning iterations, story points, etc.) So yes, I believe both positions have a very active role in an Agile team.
As far as TFS (which I'm going to assume stands for Team Foundation Server), it is a very, very robust product. In my personal opinion, TFS has more value to a business analyst. This product (among many other things) allows the analyst to engage in a thorough Agile project plan through iterations, backlogs, and stories. TFS' tool-set allows for easy management of these aspects of the project. It also allows for project forecasting, team member management, and easy-to-use UI and visual tools for story-boarding and task management.
Some of the features that an architect would enjoy including TFS' continuous build engine, configuration management, and unit testing/refactoring tools. It also has easy integration with the business analyst's planning portion by offering transparency into tasks.
I would recommend some more research online to get the most out of everything TFS has to offer. The true downside to using Microsoft products is the price. But if money is not an issue, I would definitely give TFS a look. Try a trial run of it, and do a cost-analysis.
I hope this helped at least a little bit.