I think the biggest handicap of playing JP era challenge mode is the limited dinosaur selection, you spend a fraction of the playtime in the fossil collecting minigame that you do in JW, you have a lot fewer options for how to set up your park, and it's harder to build up enough dino rating when you can only have so many high value dinos in the park. The amount available is barely even above the minimum species for the variety penalty to go away, so you're even dealing with that longer. If I buy all the DLC, I should have access to all of the DLC dinosaurs. in challenge it doesn't really matter if they fit the established story, because we're not playing the campaign, but if I had to, I would even give up the Hybrids if it meant I got all the other species.
One of the things I do like about playing in the JP era is that the contracts make sense. Unlike in the JW era, where any division can give you any contract, in JP I can actually choose what kind of contract I want by picking the right person.
Satler's contracts are a craps shoot, especially in the early game, because she is liable to give one that asks you to breed something you don't have access to or use genes that you haven't unlocked yet. Late game, once you get all the dinos and all the genes, those are easier, but they can get way more expensive then the reward is worth. However, she also offers the photo contracts, which are relatively easy, especially once you get a big herd of high value animals.
Grant is almost as bad in the early game, he is very likely to give you a contract to dig up fossils that you can't get yet, but once you unlock everything his are all really easy, "Release X Dinosaurs," contracts. The best way to get quick cash in the late game. Just get the contract, breed X dryosaurs and profit.
As mentioned above, Malcolm is by far the easiest, with either "build X safety building" or "Don't let X happen for Y minutes" contracts. Super easy, unless you have bad luck with power plants, and best throughout the whole game if you don't mind the wait.
Cabot is usually my second choice behind Malcolm for the early game, especially if I need quick cash. Most of his contracts are the easy "Add upgrade X to building Y." But you do occasionally get "increase guest income to X per minute," which can be frustrating, especially when the exact number you're trying to bring up isn't made clear.
Keep away from Hammond contracts at all costs. His are all big picture "raise the park rating to X stars," or "bring guest count up to X00," and are usually very lofty goals.
