Bitter is bitter is bitter. There are not different "flavors" of hop bitter, only IBUs, so 40 IBUs of Hop A as a 60 min bittering addition is exactly the same as 40 IBUs of Hop B as a 60 min bittering addition. Most of the commerical breweries do the same high AA hop extract as the bittering addition in all of their brews (in different proportions, of course).
So that said, you'll use less of the higher AA hops to get the same bittering IBUs in your beer, but higher AA hops are often more expensive. Cascade is about as cheap as hops get, so I'd probably use that as the bittering addition.
The flavoring and aroma contribution of hops are definitely unique to each strain, so you have to read up on the characteristics of the hop and figure out where you want their contributions to show up.
Cascade is a great all purpose hop, while Williamette and Falconer's Flight are definitely more specialized hops, so I'd also want to save those for their intended purpose. Williamette is best as a fruity/floral aroma hop and Falconer's Flight is great as either a flavoring or aroma addition for it's florals.
I'd use the Cascade as bittering, FF as flavoring, and Williamette as aroma.
If you really want to, though, FF is such a high AA hop that you could use it for bittering and use about 1/2 as much as the lower AA Cascade, then make the Cascade the flavoring hop and use the extra 1/2 fo the FF as a dryhop.
Lots of options. Just look up the hops and see where they fit best, then use them for their best characteristics.