Looking to tidy up the engine bay in the car and need some help as tyo what can and cant be taken out.

1st is this which sits over the manifold, can this be removed and the pipe which goes into the downpipe be sealed/bunged? This blows out gases from the downpipe.


This is the pipe thats going into downpipe,can it be bolted up where it goes into the downpipe?


Also, the pipes that are running the along cam cover can these be removed and a breather fitler ran as im sure there just there to help with crank case pressures.


And the sensor below, what exactly does it do?


And this which is located beside behind the passenger headlight, what does it also do? And can it be taken out or is it needed?