Unlike the Bay Area, at least from my experience in Sacramento, i don't think the difference in down-payment from a duplex and tri-plex is that significant.

The best deal I can find today is one that you buy cash, invest a rehab and when you pull out 75% of your ARV you leave maybe a small amount of money in the deal and you break even (BEFORE DISCOUNTING FOR VACANCY, REPAIRS, etc) Yes that means you leave like 10-25k in the deal and your payment becomes $3000/m and your rent is $3000 a month or slightly less.This is for my local market and for Class B or higher RE. 

This is exactly why you take a security deposit.

I assume you currently have a residential mortgage that does not have a pre-payment penalty.

When its included in a lease for real estate then the laws pertaining to residential rental security deposits in your state apply but when its separate you should have more leeway to get some additional deposit to protect you.

It’s a great way to grow faster.HELOC or Equity Tapping: If you have equity in another property, using a HELOC or cash-out refinance could help cover the down payment without affecting your DTI as much.Seller Financing or Creative Deals: Look for sellers willing to finance directly, which bypasses traditional mortgage qualification hurdles.Scaling quickly often involves combining strategies—play around with what works best for your goals.

Quote from @Jack Townsend: I heard David Greene mention a loan product that only requires a 10% down payment on the purchase price and 10% of the rehab budget.

There are mortgage recast calculators online or you can reach out to your lender.P+I payment will go from 2155 to ~1800 given the numbers you provided.

I use Buildium for tracking rent, fees, leases, and collecting online payments, but I don't use their reports for much, as I end up copying my online banking each year into spreadsheets.I've been using Rental Hero for the last hour and already impressed with it.

You have to be ready to make 3-6 months of payments on the mortgage yourself after they stop while you try to foreclose/evict them.