At the top of the studs I will remove the short 2x4 on the underside of the beam..pic 1
I will sledge in 3-2x 6's...up against the first existing stud, leaving two to be fixed.
I'll metal strap them to each other and to the underside of the beam
Pic 2 shows the sill with a 1x2 edge strip.
The new studs will be inside the framing.
The sewage pipe is far enough away from the wall that it won't hinder any work.
I will then remove the appropiate amount of wood from the two rotted studs. Then remove and replace the bad section of sill plate.
Then replace the bottom sections of the studs and sister a 2x6 just to keep
the joins honest...remove the temp studs and on to the next.