I hope it works out for you, but I'm not holding my breath. I am coming at this from a purely practical perspective - I have rebuilt a 3.2 on the driveway, and I know the hassle involved.
If one cylinder has failed through oil starvation, the others will have taken a beating. The mains and big ends will have taken a beating. You have done all the really hard bits - removing the sump and heads + ancillaries, and skipped on the easy bit - which is replacing pistons and liners. At the very least I would have got a second hand "known good" set of liners and pistons. I chose to get new parts, and new big ends in mine (acquired as a wreck after cambelt failure).
You say your mechanic is not familiar with Alfas (he is now...). Check that he knows the con rods are offset and sided. The piston arrow is easy - points to the camshaft end. The new con rod must have come from the same side of the engine, and the number on the caps must point to the exhaust side of that bank. Get either of those wrong, and it will fail within about 2K miles....
Last edited by rxe; 07-10-13 at 14:44.