What are FluentCommunity Best Practices? Sub-Domain or Sub-Directory?

I'm launching https://cinematic.ly/ this weekend, an AI-powered SaaS platform that allows startups and small businesses to create Hollywood-quality TV commercials for $50, and I want to create a private business community for people who purchase our Lifetime Deal.

I haven't messed with FluentCommunity since the beta and I have questions regarding current best practices.

1. Are you setting yours up as a separate sub-domain or are you keeping it in a folder on your main domain?
2. I'm using Prefinery and Stripe for my platform that is not WordPress-based and I want to have a webhook that creates their user account and sends off a welcome email triggered by their purchase or waitlist sign up. Do I need to do that with FluentCRM or can I do it directly with FluentCommunity?
3. Other than the FluentCommunity leaderboard, has any other gamification been added or should I stick with GamiPress for that?
4. I'll also be using Voxel Theme but won't use much of it because FluentCommunity will be the main function.

Thanks for any help!