How can I create a soft, velvety look in skies and clothing while keeping the image sharp?

In order to achieve these kind of effects i use following techniques in lightroom (It's a post processing tool, if you aren't aware of it). These may not be the most efficient techniques but can replicate what you are expecting.

Image 1:- like you said it's a long exposure shot which gives smooth water and sky. Apart from that you can use gradient filter in develop module, reduce the highlights, decrease the temperature and move tint towards pink. You can try adjusting luminance under HSL. This will give you sky. For ground try increasing shadows, increase whites and decrease blacks (for black and white hold alt button while altering, stop it when it starts clipping)

Image 2 :- It's same as image1. Use gradient filter. drag it From top right corner towards left bottom corner. this time increase the temperature and lil less tint. Increase shadows, increase whites, decrease blacks, increase luminance (not too much) under noise reduction it smoothens the image. Play around with luminance under HSL.

Image 3 :- In the image focus is on the priest and has shallow dept-of-field. Increase shadows, not too much else it'll introduce a lot of noise. Increase whites, decrease blacks. Since only priest is our main subject in the image, we can sharpen it a bit. Instead of sharpening entire image we can just sharpen the priest. Under Sharpening option hold alt key + increase masking. Image will show white background with black lines. Black lines will show you which part of the image is going to be affected. Keep doing it until priest comes under mask. Now increase amount (again not too much) and if sharpening introduces noise it can be reduced by luminance which is present just below it.