yes the HSA deduction is prorated for the year.
if your spouse is currently enrolled in a general-purpose FSA plan, then you are not considered eligible for an HSA alongside it. The reasoning behind this is that both the FSA and the HSA will reimburse expenses prior to the deductible being met. Expenses would be covered under both plans, and as such disqualify one another. This is true even if the employee does not qualify as a dependent on their spouse's plan.
However, If the spouse is enrolled in a post-deductible plan or a limited-purpose plan, they will still be considered eligible for an HSA. This means even if you are not considered a dependent, you will still be eligible for an HSA plan alongside your spouse's FSA.
