Don’t want to pay taxes on the capital gain.

It’s definitely smart to evaluate the tax and cost implications of your funding options.

Lots of local investors and professionals here in the DC area. 

Sometimes the long term capital gains are palatable and it may make sense for you to pay the tax rather than force a bad deal.

I then would have my tax cpa enter in or do it after discussing tax based items (depreciation- MACRS, reserves, year end accruals, reserves, etc.).

The mirage of get into Real Estate Investing, make ton's of money, get passive, do nothing, sip cocktails on the beach and professionally vacation the rest of your days sounds great, unfortunately it's a mirage. 

I mainly want to ask if these assumptions are reasonable and if there's anything I haven't considered:(1) multifamily units in NJ close to New York City, ~$1,000,000, 20% down payment, (2) Using the following assumptions: 4% appreciation rate, 6.5% interest rate and 5.0% refinance after 5 years, $10,000 yearly maintenance fee(3) ~$6,000 monthly rental and assume 3% increase yearly with 5% vacancy rate(4) Based on the above, the calculated IRR if selling at the 10th year is ~19% (considering tax benefits) and ~17% (without tax benefits).

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

High taxes.

Start by joining local real estate groups, narrowing your approach to strategies like house hacking or multi-family investing, and building a team of professionals like agents and lenders.