No. You can start with just yourself and add more team members whenever you're ready. But SocialKit is more valuable with your team.
When the trial ends, your organisation is locked until you upgrade. Your content, drafts, and data are all preserved so you can pick right back up after.
Yes. You need to pay for all users who are connected to your workspace.
No. You can add unlimited team members to your organization. SocialKit uses a per-user pricing, so you can pay for as many team members as you like.