With 2 Ithilmar swords you get +1 Int on both attacks.
If you model got 1 attack on profile and Int 3, you get with 1 Ithilmar sword 1 attack@ Int 4 and 1 attack@ Int 3. with 2 Ithilmar swords both attack is Int 4. With Ithilmar weapons you dont get + Int on the profile, but to the attack.
Not sure what you mean with question 2, but in your undead example. Ghouls can be hired in groups of 1-5, but if you like (and it is advised) you can hire them in 1 man groups. I cant remember if they er 0-5, but if then ofc you cant have more then that.
Hope that help, if not ask again.