Winnie, sounds like a nice build. Youll be happy with an Apache. barrel....hes does really good work!
On the mag....you cant convert a SF to a CF. The receivers are actually different(the way the mag is held in place). You'll need a CF action to begin with since youre already doing a CDI setup.

Trigger: Ive got a rifle basix sav-1 in my 280AI and really like it. Im gonna be putting 2 more in my 2 upcoming builds. Reasonably priced, and easy to install. I think Dennis has some with free shipping right now in the sponsors section.
Scooter