I would re-consider your plan. Hops love sun and water and they climb and climb, so putting them in an indoor space without a lot of vertical room runs counter to their natural tendencies.
It looks like you are on the second floor - do you have access to the ground level? If so, you could...
That's what I would do. If the yeast is dead, the starter activity should be minimal or non-existent. If you get activity and krausen off the starter in 12-24 hours, and it smells right, go for it.