Rather than cutting out a large section of the cabinet to remove it it is usually far easier to cut off the ends of the pipes and cap them with easy to use push on fittings which will work with copper cpvc or pex plumbing pipes.
Capping off toilet soil pipe.
All i can think of using would be a 4 inch bung like used to testing.
These are generally made of rubber or the cap is.
Sink 50mm 2 inch cap.
This will require considerable time and effort as well as some specialized equipment.
To permanently close off the pipe in a concrete slab the floor flange should be removed and the pipe capped below the floor surface.
Turn the cap firmly into place with your hand.
Sink disconnect pipes place end caps to water pipes disconnect out let pipe cut of to desired place cap of pipe.
End cap for main drain out let.
Cap off the drain with a toilet cover.
It is half buried on a concrete floor so not easy to cut how do you normally go about capping or plugging these.
Once this has been completed the concrete will have to be repaired and the flooring replaced to permanently conceal the pipe.
Unscrew sink lift away.
Coat the threads with pipe dope to ensure an airtight seal.
This will involve removing a portion of the surrounding concrete removing the floor flange which may have to be cut out and then the capping the pipe.
Plumbers will stock caps you will need to measure across pipe axample 100m 4 inch main pipe cap.