God-Emperor
Deity
I think it would be relatively easy to code in python - although I haven't messed with espionage points. It looks like one check either at the beginning or end of each turn that counts the units of that type that are owned by each player other than the BG in each team (espionage points are mostly done via CyTeam), multiplied by the EP per unit, and apply them using CyTeam.changeEspionagePointsAgainstTeam.
There could be info added to the unit via the Help tag that indicates that the unit provides +X
per turn to the BG and a message sent to the BG player that their Sayyadinas have given them Y
points vs team/player Z. Since they only get 3 of the resources and are unlikely to trade more than 2 that would normally be 2 or fewer messages per turn after the unit can be created.
Another possibility, which could be done instead or in addition to the above, is to give the BG player visibility at the location of all of the URUs. It could be just the one plot, or that plot plus all adjacent plots. This is probably even easier to implement and explain (and understand) and it involves no messages.
The idea is that in the source material the BG have people everywhere. Those people provide some benefit to the other factions because if they didn't nobody would have them there. But they also provide a benefit, primarily in the form of information, to the BG. So to have the game match the source, there ought to be some BG unit that provides a benefit to the non-BG players but also provides some information to the BG player. Two types of information are the simple visibility of plots and the information represented by espionage points. And maybe...
Another possible benefit is that the BG could get production bonuses for their Kwizatz Haderach related projects (or techs) for each player that builds their URU (so 0, 1, or 2 times some number) or per URU they build. This would represent having greater access to a wider variety of people/genetics to study and/or use in the breeding program. This is probably not much harder to implement the actual bonus, but could be harder to explain in a short blurb in the unit help text and it may be desirable to have some additional game text that points out the production, or research, bonus which could be harder to add (it may be doable in the python for the screens, but I'm not certain). As interesting as it is (to me), the difficulty in making it appear in the game text in the various places may make it less usable than my other two suggestions.
All of this has the weigh the benefits of implementation vs. the cost of implementation and upkeep in future versions. I think that having a variety of mechanics that are different from regular BtS is a good thing - it is one of the selling points of that most popular mod FfH: interesting things that are not in the regular game.
Since the easiest from both the standpoint of implementation and explanation/understanding is the plot visibility, that might be the one to use (if one is going to be used).
There could be info added to the unit via the Help tag that indicates that the unit provides +X


Another possibility, which could be done instead or in addition to the above, is to give the BG player visibility at the location of all of the URUs. It could be just the one plot, or that plot plus all adjacent plots. This is probably even easier to implement and explain (and understand) and it involves no messages.
The idea is that in the source material the BG have people everywhere. Those people provide some benefit to the other factions because if they didn't nobody would have them there. But they also provide a benefit, primarily in the form of information, to the BG. So to have the game match the source, there ought to be some BG unit that provides a benefit to the non-BG players but also provides some information to the BG player. Two types of information are the simple visibility of plots and the information represented by espionage points. And maybe...
Another possible benefit is that the BG could get production bonuses for their Kwizatz Haderach related projects (or techs) for each player that builds their URU (so 0, 1, or 2 times some number) or per URU they build. This would represent having greater access to a wider variety of people/genetics to study and/or use in the breeding program. This is probably not much harder to implement the actual bonus, but could be harder to explain in a short blurb in the unit help text and it may be desirable to have some additional game text that points out the production, or research, bonus which could be harder to add (it may be doable in the python for the screens, but I'm not certain). As interesting as it is (to me), the difficulty in making it appear in the game text in the various places may make it less usable than my other two suggestions.
All of this has the weigh the benefits of implementation vs. the cost of implementation and upkeep in future versions. I think that having a variety of mechanics that are different from regular BtS is a good thing - it is one of the selling points of that most popular mod FfH: interesting things that are not in the regular game.
Since the easiest from both the standpoint of implementation and explanation/understanding is the plot visibility, that might be the one to use (if one is going to be used).