For discussion purposes, here is a cumulative list of tidbits regarding HBU's gameplay thus far. Source is HullBreach Studios' twitter feed. This list may expand. Assume all items are tentative and can change, but by all means, speculate away.
1. All players begin with a shuttlecraft
2. Factions play a large part in determining storyline paths
3. Space docks serve a variety of purposes
4. Capital vessels can store fighter craft
5. Wormholes are random
6. Multiple balance board modes
7. Modes include cockpit mode, standing mode, and surfer mode
8. HBU will use its own servers
With the separate SDK Paint application for Wii U, players will be able to create custom skins for their ships. This is done through downloadable stencil packs, and the HBU pack will be free to download.
Outposts will be the source of multiplayer elements. I would venture to infer that they are specifically online multiplayer and exclusive to those areas.