They are not adjustable. The next wider size available is 35".
These shades have a liner and block some light but it is hard for me to advise if it will be "enough". They are not room darkening shades.
Unfortunately this shade will not work in a 27" window opening if you want to inside mount. It will come exactly 27" and to inside mount into a window and be functional there needs to be some space on the sides. For a 27" opening you would need to purchase a shade which takes a deduction for inside mount, stating the actual shade width will be 26.5
The reverse has a white light filtering liner for privacy and enhanced light filtration.
The shade including the brackets will be 31" , the fabric will be the same width as the roller which will be 1/2" narrower then the overall shade including the brackets ( 30.5") If you are inside mounting you must order a shade 1/4" narrower than your window opening for ease of installation and operation.
No, unfortunately this shade size will not fit your frame.
Yes ,it can be mounted on a door.
The shades retract by a spring pulling the inner cords. The maximum height is the one fold , so it is about 9".
Yes, the shades filter light.
This is a standard length if you would like shorter you would have to move to a product that is custom.