Sessions or events?

I want to host a 4 day virtual event. There will only be 1 session at a time. 
I also want to create a lobby where participants can network. Even in different breakoutrooms with different topics. 

I want the attendees to only register once for the 4 days. 
I also want to create VIP tickets, these attendees get an extra session. 

Can I do this with sessions or do I need events? 

I believe I only need events when I have multible sessions at the same time over multible days/