U can get a flange cut out from some engineering shops or ring around a few turbo places and see if they have any.
The triangle one is easy. Instead of using the factory alloy elbow u need a simple silicone bend, u will have to measure the size of the turbo outlet and the size of ur matching intercooler pipe so u get the correct size silicone bend/reducer. Then u may possibly need to extend the cooler pipe so it reaches the silicone. Clamp it on and its done.
The oil and water lines- i prefer to use braided oil and water lines, i normally get them made up from pirtek, but u will need to know the threads, sizes and lengths to be made.
Google may be able to tell u what thread the apexi turbo uses.
I have bought the lines from ebay before with good results but that was for a more common garret turbo, have a look and see what ebay has to offer.
The oil return pipe that bolts under the turbo, make sure u use a hose that wont kink and restrict the oil flowing or u can blow the turbo seals
REMEMBER- u will need to get ur tune checked, more than likely u will need a tuneable ecu,
Do u know what power the apexi turbo is rated at?