What can you support?

If you're expecting to have 20 people, having all 4 Academies plus Huntsmen plus Misc. Criminals plus White Fang plus civilians plus primary combat schools in all four Kingdoms is going to leave you with like two people a continent who can interact. 4 Huntsman Academies, 4 major primary combat schools, 4 nationwide civilian groups, 2-4 Criminal groups (Salem, White Fang, Misc Criminals, more if you have site-canon ones), either 1 unified Huntsman group or 4 kingdom-specific huntsman groups... You'd be looking at 16-20 member groups right there if you followed a similar model. In my opinion, you'd be thinking too big unless you have a member base that can actually support these numbers. World of Remnant can do it because they have the most members out of anyone in our fandom when it comes to forums, and other RWBY sites tend to die off pretty quickly when they try it with 1/10 of the member base. There isn't a lot of point to having 10/14 of your member groups sitting for months with 0 members, for example. It just makes the site look dead even when it's just kicking up.

Likewise, if you're expecting to have 60 people come in, dumping them all in Patch would be a giant squeeze and you'd be thinking to small. You'd need to run constant events to keep people interested, because Patch is a really tiny island with nothing really going on that would fit for a slice of life type game and nothing else. Which is fine if you want to run slice of life, don't get me wrong -- but there's no indication of genre so I'm just throwing stuff out there.

What is your goal for a site?

What are you trying to do? What plots are you trying to pull out? What events do you intend on running?

Why would someone join your site, specifically? Focus in on your message and the rest to suit it. If you don't have an answer for that, you may be better suited refining your concept until you have a specific pitch that you feel like has an audience.

RWBY has had a lot of sites pop up in the past year or so, but most of them boiled down to What World of Remnant does but without infrastructure as a pitch with everything I listed above being member groups and tended to die pretty quickly. World-wide sandbox with all the factions with periodic events is a LOT and requires a large member base, so I'd encourage you to go a little smaller scale because I'd really like to have the RWBY fandom ecosystem be a little healthier because more RWBY roleplayers who stick around the genre mean there are more options that people can go if they don't fit into the two boxes currently available.

There are people who don't like what the current RWBY forum landscape offers, which is why RWBY interest checks tend to have a lot of at least passing interest and new forums pop up once a month or two. There's a market there, I think, it's just offering something distinct to those people who aren't thrilled with their options at the moment but are interested in the fandom itself.

I wish you luck! Hopefully this helped a bit, because I don't think this is a question that is asked when a clear site goal is in mind. If you know specifically what you're offering and how you're going to offer it, the groups become pretty obvious from that point onward I think.