I'm worried that I'm deducting home insurance, real estate taxes, and interest twice in the program because I've been asked to enter it in two areas

If you are using the actual cost method of computing the home office deduction, you need to adjust the mortgage interest, the property taxes, and the home insurance by the percentage of square footage that the office is compared to the house.

You need to do the same with the ratio of the amount of square footage that is rented out compared to the size of the total house, and enter those amounts on Schedule E (Rental Property).

Then you need to subtract those amounts from the totals before you enter them on Schedule A for Itemized Deductions (of course, you don't enter homeowner's insurance on Schedule A).

If you had only one or the other, we could automatically do the allocation, but since you have a home office and a rental use, it's best if you do the allocation manually, and enter the correct amounts in each area.