[X] Joint Custody: While the Heart will remain within the Crystal Empire, it will be under the shared control of the Crystal Empire and the Empire of Gryphus. This will allow you to study and make use of the Heart more or less freely, though the Crystal Ponies reserve the right to protest a particular course of action if they feel it threatens the Heart itself. Most Crystal Ponies would be perfectly fine with such an arrangement. So long as the Crystal Heart remains in the Crystal City and continues to serve as the guardian of its inhabitants, they are fine with whatever experiments you may decide to run on it.
[X] Naval Base: A plot of land along the Eastern Coast will be "leased" to the Neighponese for the next century. While the Crystal Empire will retain ultimate sovereignty over the land, the Kingdom of Neighpon will exercise complete control and jurisdiction over the land itself. The land will be used solely for military purposes, and will not engage in resource extraction or serve as a civilian settlement. While neither party will be particularly happy with this compromise, neither will particularly disapprove. Some few Crystal Ponies actually like the idea of having a foreign military base nearby to serve as a deterrent to any foreign aggression.
[X] Protectorate: Aid will be provided on the condition of the Crystal Empire becoming a Protectorate of Gryphus. While the Crystal Ponies will be allowed a degree of autonomy over their own affairs, they will be considered a part of the Empire. A portion of their tax revenue will be paid to you, and they will be protected from outside aggression by the might of the Imperial Military. The vast majority of Crystal Ponies would be content with this, not believing themselves capable of standing on their own hooves so soon after their liberation from Sombra, and seeing the assistance gained as being well worth the price of some of their autonomy. And while some of the particularly ambitious members of your nobility may grumble a bit, most of your own people will likely see this arrangement as beneficial. Though it should be noted that the attitudes of the Crystal Ponies may change with time, either seeking independence or further integration into the Empire itself. Something to think about at any rate.
[X] Partial Annexation: One of the compromises that was formed and discussed at the meeting itself. The Crystal Empire will be annexed by Gryphus, but not necessarily in perpetuity. In 20 years, a referendum will be held amongst the residents of the Crystal Empire to determine whether they wish to remain subjects of the Empire, or become their own sovereign state. Both the Crystal Ponies and the Griffons of the Empire are likely to be content with this...for the foreseeable future. Elva warns you that this plan is basically "kicking the can down the road" and delaying a decision that it might be better to make now. While she won't be there to witness it, she can easily foresee such a vote being a dramatic and contentious thing that may divide the Crystal Ponies and lead to political conflict. Still, it may be the best way to ensure everyone gets what they want, even if temporarily.
[X] Neighponese Colonization: The lands that the Neighponese are eyeing for colonization have no population, no infrastructure, nothing but a line on a map to show that it is a part of the Crystal Empire. You see no reason they shouldn't have the opportunity to make use of the land. While this will greatly please Kōryū and his people, the Crystal Ponies might not be so happy about their territory being seized by a foreign power, regardless of the fact that they aren't using it.
[X] In the care of the Crystal Ponies: The Crystal Heart belongs to the Crystal Ponies. It's as simple as that. This won't prevent you from studying or even potentially making use of the heart yourself, but you won't be able to do anything without the Crystal Ponies' permission.