I would go through JKR, DR, and then Malak like you are planning, and then move towards GAS and JKL. However, I would seriously hold off on a GL, though. They are great characters and all, but for the case of SEE and Rey, you're getting one good team from the characters you farmed in exchange for the massive GP bump.
In my opinion, after you finish Malak, you need to determine where you want your roster to lean towards. Look at your guild and see if they are looking at doing Geo TB. If so, you'll probably want to start Grievous and finish up Geonosians, as well as round out your rebels and Galactic Republic. Look at your performance in GAC and figure out which teams you struggle against. Get some off-meta teams. Imperial troopers can take out SEE. They're amazing right now. Bounty hunters can take out GAS. Nightsisters for grievous. If you are worried about GL's, get a vader counter.
Think about it this way. Those galactic assault battles that show up 1-2 times a week? Being able to get kyrotech for at least half of them is going to massively increase the rate at which your roster grows. If you farm up a bunch of jedi, you can do the separatist one, and that's it.
All of the legendary characters you listed out make up a strong skeletal structure for your roster, but the meat is going to come from whatever teams you sprinkle in-between legendary farms.
