1)
It make the end a tad tougher but why not.
2)
Depends completely on how you play but since you are planning to go melee going to give only a rough outline to get at the end.
I'd say about
1 point/level in consitution.
1.5 pts/level in strength, a bit more if you can't get decent items to use the highest str weapons/armor a bit less if you plan to use the agility based weapons.
1 point/level agility (bit more if you go for the agility based weapons).
Then spend the remaining points as you see fit.
