As first - all four pictures are good, I like them very much.
First picture I like more as BW version, it's more dramatic that way.
Second picture I like more as color version since BW is a little bit flat.
But if you want to make further progress, I encourage you to step into post processing world. Since you are using Sony, most likely you have free license for Capture One. Phase One have contract with Sony and they give one free license with any Sony cameras. Or simply try Adobe Lightroom, it's free trial for month, and quite cheap if you decide to use it regularly - cloud subscription is only $9 per month or less.
As a example look at before and after work on one of my photos. Edited version has much more depth and dynamic and it is much more appealing to eye, and I even removed distracting elements (yep it's people) ;)
What you could do with those pictures using post processing is magic. As little as putting down highlights and opening shadows will give much more dynamic and another dimension to your photos.
Keep a good work friend!
Thanks for the detailed information!