Last year, I had no problem ordering the Aphra/0-0-0/Beetee 3-pack, the Chewie w/Porgs and Centerpiece TFA Rey vs. Kylo - I could have also easily ordered 6" black series item - I think it was Han w/Mynock if my memory serves.
I ended up with five of the Aphra sets - so I want to say that I was even able to go back and place a 2nd order - that's how long that 3-pack lingered.
I don't think Luke will linger as long, I am definitely hoping he will not be a "blink and you miss him" situation either.
I think the 6" Boba Fett will be the tough one.