Are we not incorporating her kids college expenses in return requirement and liquidity constraints because it is not for the coming year?
I dont have the material, but if she covers their college expenses out of her salary for example, you dont need to consider this expense in the return requirement.
Another scenario, if the question asks for the return objective of next year while the college expenses will come in the future, again, you dont need to consider them in your calculations.
Learn the general rule, and understand the variations. Read each question carefully.