Sekhur-5 dark innovation cores

I can't find any helpful information on how many of the dark innovation cores you get from sekhur-5 I'm assuming it's only 8 like one per mission and do the extra planet unlocks also give more cores on the campaign missions?

Also are the other 2 planets available in the game yet but hidden by the whole "loop mod locked by space and time" and I just don't have the right ouro gem upgrade or do they just not exist.

Thanks :^)