Forefront TMG for SharePoint 2010 application

I have few doubts on TMG. I have listed all. Pl reply for all points.

1. TMG servers are not used in SharePoint 2010 intranet application rather used only in Internet applications.

2. If any SharePoint 2010 intranet application is having a module where channel partners are accessing it & FBA implemented with SQL, is it better or necessary to deploy through TMG server? I mean is  TMG required just because partners will access...?

3. Since Microsoft is going to discontinue TMG with other forefront products should we continue with TMG ?

4. Is there any other replacement for TMG?

Thanks in advance