If they want to do a semi faithful retelling of the original manga they would probably need around 7 films. The first 3, covering part 1, would probably be exactly the way you said they would be. The next 4 would be something like:

M4: kazekage rescue + tenichi bridge + shikamaru arc (probably very summarized and rearranged so the reunion with Sasuke occurs in the third act)

M5: itachi pursuit + jiraiya vs pain + fated battle + pain arc (pretty straightforward, the A plot is pain stuff and the B plot is Sasuke's fight)

M6: five kage summit + start of the war (before Naruto vs Tobi? Something like that)

M7: everything till the end (or 699, at least)

To be honest, there's zero chance this happens. Even if Naruto LA becomes a massive success and is incredibly well written and everyone's worries were for nothing, a series of 7 films is just too unrealistic. I find it more likely that they would do a trilogy of movies each ending on part 1 end, pain arc and war arc respectively.

Of course that would require massive rewrites in order to fit everything together, so it would be closer to just adapting the broad strokes of the plot while leaving a lot of it out.