Debating last name changes and choices?

[Nicole Kislov.]

This is fairly complicated, ok. But my eldest three daughters surname was originally, Lucas. However, When I left their father (Mr.Lucas) When they were 5, 3 & 1 yrs old, I changed my name back to my maiden name; (Kislov) and changed theirs to Kislov too. They have nothing to do with their father. I met my now husband two years later, we were married within three years, and had a daughter a year after we were married. We named her Olivia, and made her last name Kislov - Taylor. (Obviously, her dad's name is Taylor.)
Recently, We were talking about surnames. My eldest daughter, Gabriella has been talking about how she thinks even though she doesn't know my dad, "really, I am a Lucas. Lucas should be my surname." She was five when we divorced, so she did know him. Can't remember well, but yes. My 10yr old, adores her step-dad, as she knew him from when she was three and he has always really been her dad. She wants to be a Taylor. My husband wants me to become a Taylor, and make Olivia, loose the Kislov. I do love Kislov though? I was thinking we change Olivia's, to just Kislov!
Any thoughts?
I have a 12yr old as well. She doesn't care. (4 girls, 14, 12, 10 and 3.) first three are biologically Lucas (and kislov!) kids. 3yr old is biologically a taylor. (and kislov!)

Thanks.
The whole point is that all, or most of us have the same last name. ?