Criticism confusion

The DeLaportes have sent you their favorite criticism of the Eiffel Tower, but they encoded the message to avoid offending the French Post Office.  

Once you've solved your first cryptogram, enter the letters you have in the cipher key to see if you can figure out the pattern behind the code to solve the second message.  When you've solved that, enter the second message at the end of DeLaporteBrainbuster.com/ (all lowercase, no spaces, no special characters) to continue.    

key

(All clues refer to uppercase letters, and may not include all letters that fall into that category)

Screen Shot 2020-03-03 at 2.37.18 PM.png

Message one:

Screen Shot 2020-03-03 at 1.57.41 PM.png

Cipher Key

arrow&v
arrow&v
arrow&v
Screen Shot 2020-03-04 at 12.52.18 PM.pn
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v
arrow&v

Message two:

Screen Shot 2020-03-03 at 2.27.21 PM.png
Screen Shot 2020-03-03 at 2.27.47 PM.png
Screen Shot 2020-03-03 at 2.27.38 PM.png
Screen Shot 2020-03-03 at 2.27.55 PM.png