Is there any advice on multi-property financing?

SFR or multi, owner-occupied or rental?

I enjoy my work and I also lead the music for my local church.

Sounds like you're on the right track towards your financial freedom.

considering taking the gains to put down on a small multi family, or SFH in an A/B class neighborhood. 

With one property I would not bother with a separate account, but keep good track of your expenses using software to categorize.

Having said that, if you don't have a primary residence yet, you could look at a multi unit and get started with that.  

On the flip side, you're going to have to ask yourself if you have any attractive alternates in which to invest your money and, preferably, are you willing to live in the in the new investment (i.e. house hack a multi-family property) or significant downgrade your standard of living accommodation.

One column I use is "Projected Costs", another is "Actual Costs", and yet another is "Paid", which keeps track of whether I've paid the bill or not. 

After that, I would like to flip and possibly manage multi-family homes, single family homes and apartments.