If you do choose to paint it make sure you sand well then use a stain blocker, followed by an undercoat then the top coats (best spray painted)......a bit of hard work and may not be successful. If all your other furniture is white then you can use this piece as a focal point and dress it up with a large white vase or white framed pictures of varying sizes, you can include a splash of colour with the white to lift the look. You could also buy a piece of white 4-6mm Perspex with beveled edge for the top leaving all other edges as is.

Have seen many vanities butted up against walls on all 3 sides and 2 sides as well as the usual wall below a mirror. No idea of operation of drawer/etc. until one was seen in the flesh. Depends on hinges, etc., what its being installed near, etc. Basin top taps are probably easiest to install. They also generally use a stop cock to turn water on or off (for maintenance & the like) underneath the vanity with the basin top taps. More aesthetics than anything else really.

The unit has an incredible view and location. Imagine how good it would look if it was being renovated for owner occupier

it;s unrealistic to expect to be able to squeeze an extra bathroom and wir into such a small space and also add a toilet into the other bathroom.. based on available information the toilet and hall is about 3.5m long but needs to lose at least 1m to allow for a new bedroom doorway and then fit in a shower at least 90cm, plus a tiny handbasin about 60cm and a toilet at least 80 cms (including knee space) to leave almost no standing room for a very skinny adult, there's no leftover space for a wardrobe in the hallway and also need to lose another meter off the existing biw or relocate the whole biw to the other side of the bedroom...and any guest would have to use the toilet in the master bedroom, as there's not enough space in the other bathroom to fit a second toilet ...a builder might do it for you but i would be very disappointed with the result and horrified at the cost for so little...my suggestion moves four doors and updates the existing bathroom by creating a separate powder room and more convenient access to the existing bathroom ...changing access to the linen cabinet makes the living area easier to furnish and there's alternate locations for the heater and ideas for a fresh new kitchen