Am I good to just make hybrids as I get the necessary dinos to make them or is there any particular missions I need to wait for?
You can always scan the Dino Data Spreadsheet to look for missions that pertain to certain hybrids. There aren’t any “create x hybrid” missions, but there are a “hatch x hybrid” missions.
The only thing I can think of is that you need diplotator and ichtyostega (I think both at lvl 31+) to unlock the boss Salamander.
There are make IRex missions. Also maybe a level 31+ IRex or Indoraptor mission. They are toward the end if still present. I posted them and screenshots here, so you should be able to search for them.
If you are doing the Story Missions, pay attention to if the Mission says have, such as the one above or if it says make, hatch, or place such as Baby Blues: “Place a newly hatched Indominus rex.”