Your understanding is generally correct and well-reasoned based on the 2017 NEC. Let's break down each point and identify any potential flaws

1. 422.16(B)(4) allows the range hood to be cord & plug connected if all the stipulations of that Section are met including an individual circuit.
Correct. 422.16(B)(4) specifically permits cord-and-plug connection for range hoods, provided all the conditions are met. A key condition is, as you mentioned, that it be supplied by an individual branch circuit.2. You can not cord and plug connect the range hood unless it is supplied by an individual circuit as required by 422.16 Correct. This directly follows from 422.16(B)(4). The individual circuit requirement is crucial for safe operation and preventing overload.3. If you hard wire the range hood it can not be connected to the small appliance branch circuit as 210.52(B) prohibits other "outlets" to be connected to the S/A circuit. Correct. 210.52(B) is very specific about what's allowed on small appliance branch circuits: receptacle outlets, and specifically those intended to serve countertop surfaces. Hardwiring a range hood (or anything else besides receptacles intended for countertop use) would violate this rule. The key word here is "outlets." A hardwired connection is not considered an outlet under this section.4. The range hood can be hardwired to a general lighting circuit as long as it does not violate 210.23 Correct. This is your most nuanced and potentially tricky point. 210.23 deals with permissible loads on branch circuits. Specifically, 210.23(A) addresses 15- and 20-ampere branch circuits. The key here is to ensure the total load on the lighting circuit, including the range hood's amperage draw, does not exceed the circuit's rating. It also needs to comply with 210.23(C) that covers appliance circuits.

Potential Flaw/Clarification

While your understanding is sound, the potential "flaw" isn't really a flaw in your reasoning, but rather a

practical consideration and a potential for misinterpretation of 210.23. The Amperage Draw

You must accurately determine the amperage draw of the range hood. Many range hoods, especially those with high-power blowers and lights, can draw a significant amount of current.

Existing Load

You must also accurately determine the existing load on the general lighting circuit. How many lights are on it? Are there any other appliances or devices connected to it?

Exceeding Capacity

Even if on paper the amperage calculation seems to fit within the 80% rule (or whatever derating factor is applicable to continuous loads), you need to consider the real-world possibility that the circuit could be overloaded in practice. For instance, a homeowner might replace incandescent bulbs with higher-wattage versions, unknowingly increasing the load.

Dedicated Circuit: Even though it is code compliant to hardwire to a general lighting circuit that does not violate 210.23, the best practice and many inspectors would likely recommend a dedicated circuit for the range hood. The load could be significant and could easily overload a general purpose circuit. The cost to run a dedicated circuit is relatively small compared to the possibility of future issues.

In summary, your statements are technically correct based on the 2017 NEC. However, the practical implications and potential for future overloading on a shared lighting circuit are crucial considerations. While allowed to hardwire to a general lighting circuit if it complies with 210.23, it is often preferable and safer to run an individual circuit, even if hardwiring, to avoid potential issues with overloading. Flag for review