Owner-occupying a small multi-family property is a smart move—you're reducing your own housing costs while building equity and generating rental income.

The cost should be getting reduced significantly. 

Are there other ways to reduce my mortgage that I am not aware of (besides refinancing)?

Increase earnings, reduce expenses, save, and invest.

He's very thorough with this standard inspections and he also offers "investor due diligence" inspections at a reduced rate.

This approach not only keeps tenants happy but also helps you maintain long-term cash flow by reducing turnover costs.

However, for a commercial property or a commercial residential (5+ unit) property value is based on the income approach and reducing expenses in this case by producing electricity factors into that math and very well might increase the valuation enough to make sense.

Partnering with others can reduce risk and access better deals.

The investors accepted it.  3 months later the buyer tried to reduce the purchase price to $2.6M to stiff arm the investors. 

House hacking with two children can be tougher than expected because you will always need to take a larger or the largest unit which will reduce your cash flow on the property even more.