Photo Frame Wall

I want to do something in our bare hallway, and I've seen several blogs that have a photo frame wall.  I've always loved the idea and our friends have a lovely one in their home, so I decided to tackle this project.  

I bought my frames at both Hobby Lobby & Walmart.  

I 'mapped' them out on the floor to get a visual and now have questions:

1).  Should I leave the letter K gold or paint it black?  or a different color altogether?

2).  I thought about adding a frame (with no glass) around the K as well.  Yea or nea?

3).  If I do some black & white photos, should they all be b&w? or will some in color be ok?  

As you can tell, I have zero sense in style and I'm sure I'm over analyzing, but I do need help!  :)

For anyone stopping by, please feel free to leave a comment!!!

I appreciate any help!