Literally my first comment on reddit, but I'm enjoying this game so far and there's not much documented yet from what I can tell. Apologies for any formatting issues, feel free to share tips on that. Perhaps we should pin this post or create an official pinned post/guide?

Misc

1. I can post a breakdown of class observations that I've made if desired. Generally I favor Gunners for single target DPS and Engineers for splash damage. In my experience, Engineers tend to be fastest (though there are exceptions here and there). My current team for rushing is 2 Engineers + 1 Gunner + 1 Healer(?). Missing a pilot does mean I miss some events, but I'm just trying to clear maps as fast as possible there and crew battles tend to take longer than ship battles.
2. Star growth rates off the top of my head: 1*/2*: 1atk/2HP. 3*: 2atk/4HP. 4*: 3atk/4HP. 5*: 4atk/7HP. I don't have any 6* yet.
3. You get 20 novas for each level. While saving up for 900 Novas is more cost effective, it might be worth it to spend a few first to get a good team of characters for leveling and completing missions.

Crew Experience

As far as I'm aware (somebody please verify), all characters gain experience at the same rate. The main difference is that higher stars will have better growths, higher level caps, and better 'skill' stats.

What does it mean

If you're trying to raise skills, prioritize the skill levels over experience: * Fuse low level characters together first before using them as experience. As an example, two level 1 1* characters will give 30 + 30 experience = 60. Fusing them into each other results in a level 5 1* character, which is worth 150 experience. It's a small difference for 1* characters, so...

• Level up higher star food characters first! Experience value is affected by stars as well. If we had instead fused a 1* and 3* character (level 1), we would get a level 5 3* character (450 experience) as opposed to the original value (30 + 90).
• Hopefully obvious, but fuse the same class (color) together whenever possible for a 2x bonus.

Crew fusion formula:

30 * ( of stars) * Level * (2 if same class, else 1)

I added a table for levels 1 - 50 at the end of this.

Orbs

Cost

Fusing a character (target) into another character (recipient):

(Recipient level) * (Target level) * 10

For Orbs, treat recipient level as 1/2/4/8 for 1/2/3/4

As expected, cost increases as level does. I haven't done the math for optimizing cost though, somebody else can feel free to check those.