If you do, I promise that I will shut up and never bring this topic up again
Who, specifically would this agreement be with?
You can't create an agreement for UQM for the same reason it can't engage in commerce. There is not "they" here. It is an open-source project. Copyright licenses you can release into the wind (from public domain to various open source agreements).
This gets back to the fundamental misunderstanding of the entire dispute. As a developer, you are no doubt aware of the concept of atomizing. Property is atomized. You have to tie each piece to an individual at the end of the day.
This is why the dispute between Stardock and Paul and Fred is not that complicated (contrary to the noise being generated).
Stardock acquired all of the registered trademarks and copyrights to the Star Control franchise and assumed several of Atari's agreements. If you are looking for a loophole to hand-wave any of these things, you are, by definition, grasping at straws.
When you ask "how much did SC make in year X" it's like asking "how much did Mickey Mouse merchandise make in 1953?" The trademark is assumed to be valid because we assume the people filing them aren't committing fraud. The onus isn't on us to retroactively prove anything. We already have the trademark and the trademark was in active use when we acquired it and since we acquired it. The copyright to Star Control 3 was legally transferred to us. The various contracts were represented to be active and assumed by us.
Paul and Fred chose to promote their new game as the "true sequel to Star Control". They even used the (R) (which kills any fair use argument even if they weren't explicitly forbidden from using the marks by contract even if the term of the agreement expired). They have refused to stop doing this.
They also chose to insist that the Star Control aliens would be in their new game and represent themselves as "THE creators" of Star Control which is a real stretch given the number of major creative contributors. I think the obvious purpose of their claim (which is a new one -- watch their GDC postmortem) is to mislead people into thinking that a new game from them will likely have the same magic that Star Control 2 did. But there's no reason to believe that given that we now know that nearly all the most famous elements that people discuss on forums were created by other people.
That doesn't detract from their awesomeness but their awesomeness doesn't give them the right to diminish the contributions of others any more than it gives them the right to claim that Galactic Civilizations "borrowed heavily" from them.
Their actions created a lot of confusion in the market.
The attorneys could just walk into court and play this video:
https://youtu.be/jwiX0eVK8Ws?t=13m47s
and call it a day IMO.
But obviously there's a ton of actual confusion to add to that.
On the copyright side, things arguably are murky but Stardock has relatively little interest in that. Stardock had every reason to believe that the 1988 agreement that Atari represented as being active and assumed by us was still in force, particularly since Paul appeared to confirm that it was back in 2013. But in any case, having the DOS games up on Steam doesn't cause any damage and there are no statutory damages involved if we turn out to be mistaken and we have removed the games for sale pending resolution.
...Which brings me back to the point of atomizing property rights.
What could Paul and Fred have copyrighted? I'm no lawyer but I've been dealing with IP for a quarter of a century as my job. I've helped invent technologies that all of you likely use frequently, I've patented other technologies you will likely use in the future, I've got copyrights and trademarks and I've handled probably close to a thousand licensing agreements over my career.
So what, exactly, could Paul and Fred possibly claim a copyright to? IMO, that would be the alien designs (visual expressions). That would be any original elements of the ships they designed the user manual and probably the script. I could be wrong on that last part. That would be about it. Which is still a lot.
For example, we couldn't just copy the SC2 ships and put them in without making changes. For example, look at how different the Earthling Cruiser is in Origins than SC2.
You'd have to make similar changes to all the ships and some of those ships would be very hard to do imo (the Spathi for instance seems like it would be hard). That's why we wanted a new license for just those ships at a lower royalty rate.
Substantially similar is in the eye of the beholder. But no one is better set up to handle it than the 9th circuit as that's where the entertainment industry is.
Hence:
Where do you draw the line on substantial similarity? I don't know. I would probably say that the third image is easily safe. The second image might be safe. The first image I'd say is most definitely not.
Similarly:
I don't like the second Spathi but I can pretty much garauntee that it would be safe from copyright infringement. And yet, the Star Control community never once argued that the second Spathi wasn't a "real" Spathi.
The point being, in every case, you have to atomize each element. What would make an image violate someone's copyright? In the Spathi's case, IMO, it would be if it had mechanical arms, was green, had a weird shaped pupil, that the eye socket wasn't completely encircled.
Following that, you say, who does the copyright belong to? The first Spathi image belongs to whoever created it or whoever they assigned it to. I have no idea who that is. The second Spathi, by contrast, belongs to Stardock as we have the registered copyright for it. We could simply reproduce that Spathi without fear. Not sure we would though.
What I wish the UQM community would understand is the tremendous marketing sacrifice we were willing to make purely out of love for Paul and Fred. We were willing to go without using the aliens from the classic series just to make it easier for them to return to tell their story in a future game -- even if they didn't want to work with us.
But that isn't the same as saying that they could just do it without coordinating together in some fashion to avoid confusion. The Star Control aliens are part of...duh...the Star Control universe. This isn't remotely controversial. If someone else wants to use the aliens associated with Star Control they have to coordinate with us to communicate to the fans how the games relate to one another. You can't use Star Control aliens and then say your game has nothing to do with Star Control. That's very confusing. You also can't say your competing game is a sequel to Star Control (can I say that Star Control: Origins is the sequel to Mass Effect?).
I have no idea how any of this will end. I am still shocked that any of this happened in the first place. Star Control ended up in the hands of Paul and Fred super-fans. Some on the UQM forums talk about being fans but none of them were willing to put up $9 million to bring Star Control back AND do so without using the original aliens out of deference to Paul and Fred in the hope that one day they would return. But instead of recognizing the tremendous boon they had received, they instead set out, imo, to ruin us after years of cooperation and support the moment they apparently got permission to work on their "passion project". You cannot even imagine how devastating that's been on a personal level.