Depreciation options on HVAC system Rental Property

This is for a 4-plex rental where I replaced two HVAC systems last year.

 

1. Can the labor portion be claimed as an expense and then only depreciate the equipment portion?

2. Do I have to use a 27.5-year depreciation schedule or is there a shorter period option using MACRS?

3. Is the Section 179 deduction an option?