Is it possible for the Bouncer class to be able to use techniques naturally without requiring the Sub-class to be Force or Techter?

yes bouncer can use them without using a class that can do it too

it is possible if they fulfill the requirements of tech to use it however bouncer doesn't really need a tech subclass to be able to use certain techs if you focus in a dex mag

The classes that can naturally use Techs are Force, Techter, Bouncer, and Summoner (and Hero and Phantom when they are released).

They even have an ability that empowers both Shifta and Deband, so yes.