I think these are two strong images, Binnur. They look great in the lytebox. They may have a lot more interesting stuff going on
in the foreground and mid-distance than optimal for showing your grand main subject, but they are great images for experimenting with NIK. My experience with Viveza is that I really enjoy the option of control points, and the structure feature adds something useful I do not really have equivalently in LR. Color EFEX pro is difficult for me to use without straying into more PP fancifulness that suits my taste. It’s fun though.
As for your question, I use LR. I have no experience with taking files from these programs to CC as smart objects but I think this has answers possibly useful to you:
http://thehdrimage.com/using-nik-hdr...-in-photoshop/