My group has +7 points to distribute as well, which results in something like 18, 16 12, 12, 10, 8. They feel a good bump above the norm. Your group is considerably higher. They are unlikely to struggle with survival even though they are only 4 PCs.
Hybrids become a lot less sub-optimal with such a high array of stats.
To make it challenging for the pcs I try and add alot of other elements to combat.
-non-combat ways to resolve combat as combat goes on
-hazards that increase the difficulty of combat if not resolved through non-combat actions as combat goes on
-fantastic terrain features that complicate combat or add a new dimension to combat
-combat and simultaneous skill challenges to resolve some of the above situations
-occaisional hard-core combats placed at the limit of their capabilities (lv+5 plus hazard)
-combat terrain that places pcs at an initial serious disadvantage against the enemies
-DC of skill challenges slightly higher and deadly elements occaisionally added.
Anyway, just try it out. Experiment what the pcs can and can't take. learn by trial and error. Combat is still just one element of the game, no matter what anyone says. Personally, the RP elements of my game are run along the same lines as every other edition I've run. And if it's not necessary to pick up the dice, then leave them still. In which case the stats don't mean a thing.
