I understand that I need to account for taxes, insurance, and other costs—Should I go with a LML and then do a refi later on?  

The more hands off you get, the lower the returns.

Real estate investing has been a passion of mine for time with my mother also having invested early on where I likely have gotten the love and desire to follow similar foot steps.I have taken last 6 months to educate myself and currently own a single family home as primary residence and would like to expand to multi family properties (2-4 units) for additional stream of income, not to mention potential tax benefits for long-term investing.Based on current living situation, I have a fair amount of equity established in my primary residency along with having enough cash to either pay off house completely or use towards investing in a multi family property.Given that I'm the sole source of income for our household with my wife being the home maker for our two kids under 2, trying to weigh out risks with getting started now or perhaps waiting. 

Low barrier to entry, low taxes, landlord friendly, some amazing class A and B suburbs and a strong urban core. 

As for by-the-room rentals, many lenders won't allow that and if they do, they qualify you off of the long term market rents (which, as I'm sure you can imagine, would be considerably lower than the actual per-room rents).

Typically, higher income areas have lower crime, more amenities, better schools.  

If you need financial help, ask under the "Finance, Tax, and Legal" forum.

The Heloc can also pose as a debt obstacle since its an open end mortgage a.k.a credit card.a mortgage is also set up over 30 years so it offers a lower rate and payment. 

For tax purposes, rental income is generally recognized in the year you receive it, not when it is paid.

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.