For night landscapes, it's better to use manual exposure to have full control over exposure and Depth of Field, and also to avoid blowing out the highlights.
The highlights tend to be blown out in any semi-auto (such as aperture priority etc.) or auto (normal program) exposure modes because a large part of the areas in the picture is dark (such as sky, sea or low light or unlit areas) and therefore the camera attempts to brighten up the shadows areas with more exposure than is necessary to expose for the highlights, especially when you're using some form of average metering (such as matrix, centre weighted etc.)
In the 1st and 2nd pictures, the left side of Fullerton is blown out and this is especially so for the 2nd picture where the exposure is more. In the 4th picture, the over-exposure is clearly seen in the "MANDARIN ORIENTAL" neon sign which is now blown out and illegible.
Below is an old picture (which is a bit over-sharpened though and composition isn't good without any foreground to complement the background) which shows that "The Oriental" neon sign is legible if not over-exposed. This picture was taken by a Nikon Coolpix 5700.
With manual exposure, you can look at the histogram of the picture taken and then adjust your exposure so that you have full control over the exposure of shadows and highlights. Very often, as the dynamic range of the scene is more than what the camera's image sensor can capture, you have to decide where to strike a balance between under-exposing the shadows and over-exposing the highlights. However, some of the details in the shadows can still be brought back up in post-processing whilst nothing very much can be done to bring back the details in the blown out hightlights. So watch the highlights on the histogram carefully for exposure.
A general exposure guideline for buildings landscapes such as those above is "888" :
ISO 80 (approximate ISO 100)
F/8
8 seconds
Depending on your distance and overall brightness of the scene, change the exposure from there. Further = more exposure than the above is needed. Many bright lights = less exposure.
Of course, you may balance the aperture vs shutter speed to achieve the same exposure. For e.g. If you're using F/11, then the same exposure as the above would be 16 seconds at ISO 100. If you want to use F/16 for great DOF and/or star-burst effect on bight light points, then 32 seconds. etc. Also try to avoid using apertures smaller than F/16 for an APS-C size image sensor DSLR because diffraction starts to set in at around F/16 and increasingly more more apparent with even smaller apertures, causing a lost of sharpness.
(p.s. To avoid having too huge dynamic range in the scene, better time to take the CBD would be around 7pm-7.45pm or thereabout where is still a bit of light from the sky and you can get some colours in the sky. Apparently, the 1st and 2nd pictures were taken around that time and a check on their EXIFs confirms that. Also the scene would also look more dramatic during working weekdays when many of the rooms in the CBD bulidings are lighted up as some people are still in the offices. Last but not least, the weather is a key factor too. If it's raining, it would be dark, gloomy with grey sky. If you want clear sky with some colours and distinctive clouds in the picture, then it has to be a fine weather day.)
