I was initially surprised they'd asked for the game to be postponed but then someone pointed out that they're unlikely to win the PL now, so this competition might have taken on more importance for them.
Presumably they would use the next two midweeks to play the games.
As for the final, I was thinking Kavanagh initially but Attwell could be a good shout - although might not be popular with Arsenal!
The FA Cup final is also interesting - I think many of us had Pawson as the favourite for 19/20 before Covid changed everything so I always had him in my mind to referee the first FA Cup final with a full stadium again. But Paul Tierney has got more of the top games in the PL so perhaps also has a decent chance?