fascinating concept - very waterworld. i love it.
but i wonder how big can the structure get vertically and horizontally? what happens during a (rare) typhoon or tsunami? what is in place to guarantee a democratic approach to governance, and would there be citizenship and all the other things that come with being a part of a country?
why on earth does seasteading need a host country??
Your former engineering questions answer the latter question about why a host country is needed.
Previous seasteading projects focused on having a seastead out in international waters (200nm away from any country) with estimates being in the hundreds of millions of dollars (just look at the cost of an oil rig to get an idea of cost). The hope is that we can come up with some better engineering that will get that price down over time. There are so many different things to consider when trying to create a seastead in international waters that not experimenting would be a rather foolish way to risk so much money.
This has resulted in considering a phased approach.
Phase 1 is building a pilot seastead in a protected lagoon of a host country.
Phase 2 is moving/building 12nm out from that location giving more sovereignty while having the challenge of open water, while maintaining a lifeline to the host nation.
Phase 3 is full sovereignty 200nm out in international waters.
Having a host country lets Blue Frontiers build in a protected lagoon which allows for working out such concepts as you mentioned, governance, citizenship, sustainability, engineering, etc. All things that might sound good on paper but once on an actual seastead might have complications that nobody ever considered. It also allows some hybridization so that baby steps can be taken. Food, for example, will be difficult to grow initially and is likely more cost effective to just buy it from the host nation. Internet can more easily be transmitted to the seastead. Many initial requirements can be covered in an incremental approach which allows Blue Frontiers to raise a smaller amount of money up front and grow from there.
A host country also gives the protection of the military which would be an even larger economic cost to a fledgling new seastead in international waters.
With the Special Economic Zone Blue Frontiers will be given some economic leeway which will allow for some initial experiments in governance but will still be under French Polynesia criminal law so rape, theft, murder, etc will have a fully functional justice system to take care of such things without needing to start from scratch.