I'm no Nostradamus but if I had to place a bet I'd bet on rates holding flat until/unless it was obvious there was significant thawing in the residential housing market, and I don't think that's coming any time soon until wages come closer to catching up with prices.

A duplex is a great way to get your feet wet in multifamily investing, giving you two rental incomes under one roof, which can be a great balance between cash flow and passive income.I’d also suggest looking at markets that offer solid rental returns.

He wants to focus on large ticket items for property managers: roofs, turns, hvac replacement, whole house painting, things like that.

For your major capex expenses, I assume AC, WH, roof, you would need to get in touch with a local contractor (or two). 

Is it legal in Oneida County in Upstate NY to charge tenants a flat rate for utilities?

When purchasing, things that will amplify rates are roofs that have less than 10 years life, old water heaters, flood zones etc.

It seems as if the options for owner-occupiers of three-unit properties are pretty limited, especially if the building has a flat roof. 

If the seller is still on the property after you close (you negotiated delayed possession), I wouldn't be opposed to doing exterior work (roof, landscaping, concrete, etc.), but I wouldn't do any interior work.

We politely point out that we'd require ownership to do this and they always drop their request.This is even the case with Flat Fee PMCs.

This included installing new tile flooring at the front of the house to enhance curb appeal, upgrading the electrical panels for safety and efficiency, and putting on a new roof to ensure long-term durability.