I've been thinking of deleting facebook but if I were to, would every app on my homescreen that is linked to my facebook be messed up data wise or same thing with websites ect.
Are you talking about deleting your Facebook profile or the app itself?
If you are going to delete your account the apps that require a Facebook login will just open up Facebook login in safari window. But you just won't be able to sign in...
Same goes for if you delete the Facebook app, however you will be able to sign into it with the mobile version which opens in safari.
Nothing will happen if you delete the app. You're Facebook information is still on the iDevice as Facebook account info is installed into the Operating System, so you have no worries about your apps being messed up.