A difficult headline puzzle

Headline Puzzle

(1) MJHGNP GJQ

(2) CSLAAPO CLUPAHIMMO'V IMVHLJPV

(3) KNM NPCL-AE-KNM-FPD YHRMT FPD

(4) BGKMBP LCDVMLSD MJVSDEL'P KGFWVR

(5) AGPIB DKEUSGT & EKBYGC WTGAW TKMXIUC?

I think this headline puzzle is difficult even with a computer. My simple substitution solver only gets headline 2. Using a list of 750,000 words/phrases, the single headline key solver applied to the encrypting alphabet from headline 2 gets 16 possibilities for keys with hat length less than 10. However, among those 16 possible keys, only the correct key's columns can be joined into a slidable alphabet.

Some solvers:

Pencil and paper: ENDEAVOUR , JUDE , Phillies, MAB, Becasse, D., Applejack, DOPEFISH

Computer: GGMA, The Rat, Doppelschach, ANCHISES, FOMALHAUT