I'm a foreigner, lived in Southeast Asia, never been to Japan and there's a slim chance of I'll ever travel there but your contents are educational for those who wish to travel in Japan and I thank you for the effort and passion you put in these videos.
Use Skyliner only if you live in Ueno. The other major stations in Tokyo (Shibuya, Shinjuku, Ikebukuro and Shinagawa) are all served by the Narita Express by JR East. Yes, it's slower that way, but you don't want to change onto a busy commuter train with three bags or sth.
I don't even know whats the point of the other options. If you take the normal train its like a couple yen cheaper, and the narita express is more expensive and slower too
It's not often full, you reverse your seat when you buy the liner ticket on the ticket machine, you pick the departure time and it shows you available seats