I am looking to refinance a 3-unit mixed-use facility (one-third commercial, two-thirds residential) in rural Upstate NY. 

Are you referring to personal auto insurance vs. commercial auto insurance or a business usage classification on a personal auto insurance policy.

I've come across some interesting niche strategies like buying small plots of land and slowly building, investing with a team/syndicatikn (if you find a good one), or even funding smaller infrastructure projects for commercial properties (e.g., electrical, plumbing, etc.). 

For SFH, small MF, most commercial, etc should have a correction. 

Investment Info:Mobile home commercial investment investment.

You will have to get a commercial loan.  

Above 4 units is considered a commercial property.

Quote from @Adrian Clapp: Montana’s proposed law would lower property taxes for primary residencesand long-term rental properties while increasing taxes on second homes and other high-value properties.Pigeon Forge area made all STR's commercial properties and substantialy increased the property tax on these properties.Unfortunatly this is the cost of doing business. 

I believe commercial loan would expect 25-30%.

You wrote commercial, but then talked about offices specifically.