What duty stations are available for 19Ds? Do they get attached to SF?

Typically infantry will get attached as well as other supporting mos but you dont want to be attache to SF unless you're SF. I've been assigned as their force protection and none of it is cool or high speed. Their are many places Scouts can be assigned, depending whether you're heavy, light or airborne. Pretty much all of the main bases would be available unless you're airborne, just like any other MOS would limit your options but is definitely worth it. My experience as a scout, I've been to Grafenwohr Germany in 1-91 CAV (ABN) 173rd IBCT (ABN), 1 BCT 82nd ABN in 3-73 CAV currently a Healthcare Recruiter (yes as a scout). So you could really end up at any of the main duty stations. Hope that gives you some insight.

1. Nearly all. 2. Yes but it is awfully competitive and a bit rare.

Any Mech/AR unit has the 19D,, google it. NO SF has 0 armor capabilities, and no AR assets. The closest would be some sort or joint OP where AR/Mech units might provide blocking actions.