I think it will have this, its just speculation from my part:
• It may have 2-3 new maps, since this will most likely be its own campaign, players will have a stronger attachment to the story of the original JP trilogy. So we may have an extra map to play with in this pack, extending the overall story.
• San diego would be a new location, but there is also a possibility of japan and europe as this is probably a JP story that became successful as Hammond intended.
• Segisaurus will most likely make her debut, and will be the same size as the homalocephale. She is the last of the dinosaurs on the
original Nublar map.
• There will be 2-4 more additional dinosaurs introduced alongside her, so we may get 3-5 in total. And it will include some oddities and some iconic ones like oviraptor, a prosauropod, and protoceratops
• This dlc will be heavily focused on the guests. JP has a more market focused story of gathering guests from around the world, more than JW's message of the dinosaurs as living breathing animals that need care too. This would mean we would get some new attractions to go alongside our parks and facilities to cater to guests.
• Terrariums would be introduced: These buildings will be like those of zoo tycoon and planet zoo and house in dinosaurs too small to fit into the game's current dinosaur engine like Compsognathus and microceratus. We saw how the homalocephale is so small that darting her is possible but more difficult, and that she is submerged underwater when she walks to it, any smaller would not be as enjoyable in technical terms. So terrariums would make sense as a building that boosts fun ratings that is not a bowling alley or arcade.
• BIrd cage: In JP3, we have a dome for the pteranodon, and the pteranodon were visibly part of JP since JPTLW. Like the terrarium, the birdcage would house flying reptiles that would act like the terrariums.
• Some JPOG attraction ideas, like the tower with 360 vision, an underground viewing dome, or a balloon ride. This pack will introduce many ways to enjoy the park's dinosaurs.
• Safari jeeps as you noted. I do not think they will be driveable as the original JP jeeps were on a rail, but you could drive a classic jeep that is run with fuel. Would make for some scary power outage moments.
• Skins! As you also stated, there will be skins for our legacy dinosaurs including T-rex, triceratops, ankylosaurus, brachiosaurus, and most important of all: The raptors.
These are some of the things I think will come to the JP pack if it comes. I do think that the JP pack would have the most love of all the expansion packs as it is heavily based on the beginnings of this franchise, and fans who clamor the original JP would want to get into this pack with great expectations.