Breakdown of Achieving LeanFIRE

It sounds like you are well on your way to achieving leanFIRE (Financial Independence, Retire Early) by relying on passive income streams like rental properties. From what you've shared, here's a breakdown of your situation:

Strengths:

Rental Income Coverage: Your rental properties cover your monthly expenses, which is a major advantage for leanFIRE. This gives you a stable income without relying on selling assets or drawing down from investments.
Asset Base: Your $900,000 net worth is solid, with a significant portion in assets (including the primary residence). Additionally, the $60,000 in taxable brokerage and $50,000 in retirement accounts give you some flexibility for growth and future needs.
Self-Employment: Staying self-employed but being selective about the work you take on could give you more freedom while still generating income. This can help bridge any gaps if needed.
Healthcare: Access to healthcare through ACA is a key consideration for self-employed individuals. The affordability of the plans can depend on your income, but it's manageable if planned carefully.

Considerations:

Dependents: With 4 kids, you’ll want to account for potential future education costs, especially if you plan to pay for college or have other significant expenses for them. While your passive income covers current expenses, these might rise over time.
HELOC: Having access to a $400,000 HELOC gives you flexibility, but it’s important to remember that tapping into this could come with costs or risks, especially if interest rates rise.
Longevity of Passive Income: Ensure your rental properties remain profitable in the long term. Property management costs, maintenance, and vacancies can fluctuate. Having a 5-month rent reserve is good, but you should also factor in potential for market shifts or unexpected expenses.
Retirement Funds: Your $50,000 in retirement accounts could provide tax advantages in the future, but without contributions or growth, it might not be a large enough cushion for long-term retirement needs unless you continue to contribute. It’s good that you're planning to fund Roth IRAs and investments.

BaristaFIRE vs LeanFIRE:

BaristaFIRE typically refers to having enough passive income to cover basic expenses but still working part-time or doing selective work for extra income or benefits (like healthcare). It sounds like you're leaning more toward this, especially with your selective approach to self-employment. The key difference between leanFIRE and BaristaFIRE is the degree of independence from work. LeanFIRE usually implies no need to work at all, relying entirely on passive income and investments, while BaristaFIRE might still include some degree of active income.

Possible Gaps:

Unexpected Expenses: Consider a buffer for larger-than-expected future costs, such as healthcare, emergency home repairs, or other big life events.
Market Risk: Rental properties are a great income stream, but they are also subject to market conditions. If property values or rental demand drop, your income may fluctuate.
Retirement Plans: While your self-employment funding seems solid, you might want to review your strategy for retirement beyond what’s in taxable accounts or property.

Conclusion:

You seem to be on track for leanFIRE, with a reliance on rental income and selective work. Just keep an eye on future expenses, healthcare costs, and the stability of your passive income. A “BaristaFIRE” lifestyle could work as a bridge if you're looking for a balance between work and leisure while still being financially independent. It may also be helpful to talk to a financial advisor to help forecast long-term expenses and growth.