welcome aboard, tank... congrats on the car!!! remember, we want pictures, so we can make cosmetic suggestions that you may consider, based on what the other folks may have done to the same color combos...

about the rear wiper arm - before buying OE, search on this board, there were some rear wipers done that have improved the appearance of the piece in comparasion to the OE without compromising the functionality...

the window - chances are, it is the regulator - be careful about buying the ones off ebay, sometimes they are not a 100% fit as you have noticed with the oil cap... and a lot of times, the piece that is broken is a $2 plastic clip - 2 of them go to the front and 1 to the rear glass... i actually bought like two dozens of them from a dealer, they lay in the garage, in case of the problem, i have them handy...

the I-6 engines (as BMW motors in general) are very sensitive to the cooling system, if you replace the hoses, the pump, blah blah, make sure you properly bleed the system from the airbubbles, otherwise you will start getting strange temperature fluctuations...

you said - factory single display in the ceiling... i know that the rear entertainment system used headrest monitors and a vertically installed dvd player, i don't recall the ceiling mounted ones... nevertheless, if the cost of the repairs will approach $200-300, you may wish to consider headrest DVD players - i have (obviously chinese!!) two of them, they are independent from each other, play all region discs, play different SD/MMC cards, and have USB connection... since the OE rear entertainment system is NOT really interacting with the rest of the car, other then drawing power, i went aftermarket on it - besides, i can always pop the OE headrests back in, it is a reversible process... the biggest challenge for you will be color matching the HR to the rest of the interior...

on the steering wheel adjustment - there might be a fuse... i need to look at the blueprints on the WDS to see if there any...

well, congrats, and welcome!!!