You continuously say you plan to use wifi…
My assumption here is that you plan to have this network accessible to any commercial wifi device on the market.
This alone is a problem as part 15 will not allow the network to operate in this way.
However lets say for a second you want to work under the US Amateur Radio Part 97 specification.
This would allow the use of high power both in the sky and on the ground, it would however NEVER be allowed use in a cubesat as only ITU Region 2 (USA) has access to the 13 cm band.
You also have to take into consideration that other counties use this radio band for other purposes and that your satellite network would interfere with tier own.
Unless you run in a specialized radio band, this thing will never get off the ground as no government in their right mind would allow you to launch it.
Don’t get me wrong, I want to see it. but have you thought about this yet?
EDIT
So after reading a bit I wanted to add to this post.
You want to use this as a one-way network… so that most users are just receiving information.
Most commercial wifi devices don’t work in promiscuous mode, meaning they have to authenticate with the station. That right there blows the idea of standard hardware like phones from being able to receive anything from this network.