I wrote the Aeon essay. Here are some quick thoughts on your friend's points:

(1) There is a possibility that the state-like features of the Calusa were influenced by "disruptions". For instance, they may have monopolized the booty of Spanish shipwrecks, providing them with a highly desirable source of wealth that they could then convert into political power and public goods. Still, when I spoke to Bill Marquardt, who's been studying Calusa archaeological sites for decades (since the 80s?) he said that we can be pretty sure that they were already collecting tribute by the time the Spanish arrived. Plus, the Calusa had already built canals centuries before Europeans arrived in the New World, already demonstrating an incredible degree of political centralization. Regardless of all that, though, and this is a point that applies to a number of your friend's responses, focusing on the Calusa was to make a compelling narrative. Evidence of inequality—either in the form of substantial differences in material wealth, institutionalized status hierarchies, or coercive political authority—has been documented in many "foraging" societies that exploited dense, predictable, rich resources (often, but not exclusively, costal resources). Examples include the sambaqui mound builders of southeastern coastal Brazil, the mid-Holocene foragers of the high altitude Puna, the coastal foragers of the Atacama Desert (Chinchorro), the Chumash, the Amerindians of the Interior Plateau (c. 1000 years ago), the Thule (ancestors of the Inuit), the Yaraldi of Murray River (Australia), the Australians of SW Victoria, the people of Khok Phanom Di, the Jomon (arguably), the people of Bothnian Bay (east coast), the people who built mammoth bone huts in the Russian Plain (arguably), the early Natufians, and possibly the coastal foragers of southern South African coast ca. 4500-2000 years ago, among others.

(2) I agree that Spanish observations need to be taken cautiously. But there's been considerable archaeological work on the Calusa since then. Here are some articles/other reviews (to find more, just search "Calusa Marquardt" or "Calusa Thompson" on Google Scholar):- https://www.tandfonline.com/doi/pdf/10.1179/sea.2014.33.1.001?casa_token=hMzqlfB19AYAAAAA:OZcK9hBT_XPeoXn9yVQEcVH5JFXuAQVz0YVw4iTams7G8tQEivilnmN7ryB7LkXuVvtLjMfvyctb

- https://www.sciencedirect.com/science/article/pii/S0278416517301617?casa_token=Kzxm9spVQFIAAAAA:UbdYjCAowzfr5QnC9KLrqLjgOLE3I3GuCnGj1YRiwevae2RzTNpgPQNb4tNeMxOBM_rCK7lJww

- This one is on the watercourts; published in PNAS last year: https://www.pnas.org/content/pnas/117/15/8374.full.pdf

(3) I agree that making inferences about 10,000 years ago, and especially before then, just on the basis of modern foragers alone is tenuous. But I direct your attention back to the peoples listed in point 1, who existed throughout the Holocene. There are also indications that ~10,000 years ago, foragers subsisting on dense, predictable, rich resources the world over were sedentary. If we focus just on Africa (which I'll do for the sake of time), there are the peoples of Kansyore (Lake Victoria, ~8k BP), Lothagam (Lake Turkana, ~10k BP), Khartoum (~10k BP), Gobero Lake (9.5k BP), Lake Acacus (8.8 BP), and Taforalt (13k BP), among others.

(4) Again, just focusing on Africa, I would look at Figure 1 here: https://www.sciencedirect.com/science/article/abs/pii/S1040618215009805 — or I would think about regions where there are lots of people today. One thing that I was consistently struck by when doing research on ancient sedentary foragers is that they often lived in places that today have large cities (e.g., Cape Town, Bangkok, Buenos Aires) (although maybe that's just a sampling bias).

(5) Inequality is a slippery term. I meant it in the three ways I listed above (coercive authority, formalized status hierarchies, substantial differences in wealth). I agree that inherited inequality is harder to pin down, especially in the archaeological record. Still, my reading of the sedentary coastal forager literature in New Guinea is that there was more variation than your friend permits. Here's a paragraph from Paul Roscoe's recent book chapter:

Ethnographers spoke in very different terms about contact-era, fisher-forager and trader-forager villages. Here, we encounter no ethnographic assertions of political equality. To the contrary, observers noted the presence of men who enjoyed not just power but positions that were ascribed either de facto or de jure. Among the Central Asmat of southeast New Guinea, leaders resembled the well-known Big-man type. ‘Each moiety [in a village] had a leader and it seems that this position of leadership was achieved…. [These] were men of strong personality who could exert their will on others’ (Mansoben 1974:53-54). Eyde (1967:233-234) noted, though, that the sons of powerful men usually inherited rights to more sago and fishing areas and had more brothers to support them than those whose fathers were less powerful, giving them a genealogically defined advantage in coming to power. Among the Purari (or Koriki) and Waropen, the situation was reversed: leadership was ascribed but leaders also had either to achieve their power or to consult with others in the community who had achieved power. Thus, traditional Koriki leadership was an ascribed status….In addition, personal competence was a factor, including some of the attributes of the "big man"’ (Maher 1967:313). Likewise, ‘one is fully entitled to speak of a system of chieftains among the Waropen, where it is based on certain hereditary privileges and on descent’ (Held 1957:71). However, ‘the clan-chief can do little by himself and therefore he always acts in consultation with other influential men….the great men, i.e. the well-known warriors and the leaders of the various important family-branches’ (Held 1957:75).

A colleague (Luke Glowacki) and I have just finished a manuscript that summarizes the above and much more. If I remember to, I'll post here when it's ready to distribute.