Can a brand-new group start together on day one?

Yes, that is the point. These servers usually make it easy to settle as a group with quick trust or claim sharing and a community that expects friends to invite friends.

What keeps our shared base from getting griefed?

Typically land claims plus active moderation, often with rollbacks. Always check the rules and enforcement, since welcoming does not automatically mean fully protected.

Do we need to join a town, faction, or clan system?

Usually not. You can run independent with your friends and still opt into trading, events, or community projects when you want.

Will established groups steamroll us?

Less than on harsher servers. The culture and rules tend to discourage spawn hunting and bullying, and progression systems are often tuned so new groups can ramp up without being blocked.