Also a side thing, since we can do chatting in the lobby, do we wanna do that to make things more hassle free? At least for choosing stages.
A possibility. Though for personal reasons I'd rather not do voice chat.
Also to answer your timing questions, that is a time which people could say "I'll be there" and so that it could be structured around it. The bulk of the matches will take part then; that's still the plan; but if you're both online then it doesn't hurt to start early!
It's a similar sort of format to the Pokemon Tourneys we did last year. First time we did it we had people waking up at 4AM and ending at 2AM because of timezones. By the very nature of the site and the fact we're all across the world; getting people together for a one-on-one competition which could take some time is near impossible. Hence giving a little leniancy works in practice.