It is unknown if they will be made available again in future seasons. D3 Season 3 Achievement rewards a Portrait and Pennant.
I see that Diablo 4 will take the best from the 2nd and 3rd parts. I wanted to get my money back in the first hour as the servers were down. So far I have played 30 hours, I must say a good remaster. I see that the original Diablo 2 is the best to this day. The two couples shown are to be replaced with a single equivalent couple I didn't play Diablo 2 much.