Jitsi Codebase execution flow

Dear Community,
I have decided to use Jitsi for one of our upcoming product. I am already finalizing devlopers for React, Nodejs & Java to customise the product.

Q1> I am not sure what would be the final skill set required within a team to comfortably able to customise the product? Can anyone please list?

Q2> What is the flow for code execution when Jitsi is running. I understand that meet is the client application supported by JVB, Jigasi, Jibri, Jicofo etc from server side. Anyone could help me with actual flow of JITSI code - client side and server side?

Q3> What are the minimum infra requirements to run the conferences with at least 100 participants. (We are using AWS for our deployment)

Thank you in advance.