On some A series engines there is a water gallery in the block just behined the engine mount. This is where i picked up water from. For the qwater return you will have to go to the suction side of the water pump. There is usually a heater hose atachment on the steel tube that the bottom hose goes on, T in there somewhere.

For oil pressure you will have to T into where the oil pressure switch goes. I highly recomend you not use brass for this as ive had them crack from engine vibrations + the weight of the oil pressure sender and turbo feed line.

The best setup is to run flex from the oil pump to a block mounted to the skirt somewhere and then flexable line to the turbo. the oil pressure switch gets mounted on this block.

The oil drain tube in the sump must be located higher than the oil level. It can be done while the engine is in the car by sharpening a steel rod of about the diameter of the tube you intend to use. shape it like a like a pencil and then grind 4 flats on it (a bit like a very sharp church spire).
Use a hamer to drive a hole above the oil line in the sump, rotating the sharpend rod as you go. Doing it this way you wont get any swarf in the sump as the metal just folds back inside the sump. Then weld in your piece of tube.
Sound a bit rough but ive done this several times and is the way Saffari turbo kits are fitted at autherised instalers.

In an ideal world the sump would be taken off.

Hope that helps.