When active duty members deploy and place their stuff in a storage unit for the duration of their deployment, can those fees be added under deductions?

This is a deductible expense, but only if you are moving.

If you're a member of the Armed Forces on active duty, you may be eligible to deduct moving expenses if your move was due to a military order and permanent change of station. You may be able to deduct your unreimbursed moving expenses for you, your spouse, and your dependents.

Deductible Moving Expenses - You can deduct expenses that are reasonable for the circumstances of your move. Your eligible moving expenses include household goods, personal effects, storage, and travel expenses (including lodging) to your new home. You can’t deduct any expenses for meals.

Moving Expenses