I've been thinking of a getting Mint Cinnamon dual boot for my next computer, so I won't have to use Windows 10.
Lenovo now sells Ubuntu laptops, but no dual boot from what I can tell.
You are on the absolute right track with the Mint Cinnamon. As a win 7 user you will be comfortable right away.
I just took a brand new Lenovo out of the box and installed Mint Cinnamon as dual boot.
The only thing I ran into was they wanted several BIOS settings in several places to allow it to install.
Works great! If you ever do it let me know and I will make note of those settings for you so that you can copy them to set up yours.
Important note... Once the BIOS is set right the Mint installer will make it dual boot for you slicker than snot... :)