umm, no. you can skip getting decoy, its just really inconsistent to do the brute trick in pauper's drop without it. Seeing as you're doing a segmented run it's probably better to skip it. (you wouldn't need the big sisters extra adam).
Something I did a while back which might also be faster is doing a death warp right after activating the train station to get to the train a bit faster. I'm not sure how you could manage this as I always used the big sister. Maybe bring an item from in front of the vita chamber and set it on fire?
I just noticed a small potential timesave in Pauper's Drop that you might want to use for the segmented run. If you die after getting drill dash you don't have to wait for Sinclairs' messages to play out before breaking through the wall. It seemed to save around 20 seconds when I timed it if you get a quick death.
Is there a key you should press/hold when deathwarping to spawn into the vita-chamber quicker? Sometimes it respawns pretty much instantly yet other times there's a 3-4 second animation back to the chamber.
You might try picking up the typewriter + throwing past the barricade, unless you can drill dash while holding something ( i think you can, but im not 100% sure).
There isn't any consistent way, just place the typewrite on the staris, walk on top of it (make sure you get pushed on top of it and aren't standing in it), then just grab it with telekinesis. Most of the time you'll probably pick it up and fall to the floor but occasionally you'll get a small boost, with enough patience you'll get the really good boost to the top floor, but then you need to make sure you move in the air to land up there and not fall all the way back down.
Using the trick to skip 'Gravity Well' in minerva's den and optimizing the fights a bit, I cut over a minute and a half off the old WR
If we could find a way to die (quickly) once we get out of the water in the very beginning of Minerva's Den we could cut out a bit of walking due to the 1st vita chamber being so far into the level, unfortunately there isn't much to work with.