If its going to be a while before you guys are playing this campaign I would recommend holding off on character decisions. The Advanced Class Guide should hopefully be out before you guys play and who knows how those classes will have changed from the playtest. It may be that one of those classes better fit the theme/RP Background you guys have in mind for your characters.
With the above party I think you have already hit the nail on the head for most of what would be problematic. Though I can add it does look like there is also a distinct lack of decent swarm fighting techniques (area effect sorcerer/wizard spells or alchemist bombs). If the Mummy movies taught us anything its that swarms of scarabs are just lying around waiting to devour tomb explorers.
Now the thought of that just gives me the willies... *shudder*
We just like to gameplan our characters ahead of time - it gets us excited about the AP, keeps us committed to the group. Its a living document, though, nothing etched in stone.
Case in point - I was the one who was going to run the Dervish and now I'm seriously rethinking it. The Summoner, eidolon and Barbarian should be more than enough to handle front-line duties so I'm thinking of running a Cleric instead, one my husband designed for Slumbering Tsar but was never used. I figure an Evangelist taking the Glory-Heroism Domain will let me load up on buffs the group can use, will give me access to strong 'face' abilities and open up those healing spells we know we're lacking. Offensively I'll use Sacred Summons and eventually a little 'bad touch' action with Planshift as a perfected spell.
As an aside, I don't think anyone in our group is going to be taking advantage of those 'hybrid' classes any time soon.