I am leaning towards Gate 90 being a social network with a marketplace and a events calendar. That being said, I see no need for a separate forum on a subdomain, even if the network will be launched a while after some of the other sites.
I like a theme called Kleo as it looks flexible enough to work with my plans for the main site. It helps that it is already integrated with WooCommerce and The Events Calendar, two major plugins besides BuddyPress that I will use to create the site. I was considering a different script to power the social network, but it needed too many paid plugins to make it work properly like I want it too. Also all the themes I was considering supported BuddyPress and not it. That alone says how much support BuddyPress has in the community and how it’s the go-to plugin on WordPress for communities.
Gotta run so take care! 😉