I had a quick look last night, IF we make the final or both the CL and the FA Cup, assuming more games don't get postponed, they'll be 5 free midweeks to rearrange a maximum of 5 games. 1 of those 5 is the midweek before the LC final which I still think Arsenal away will be rearranged for. No way will the season be extended so anything different from this will mean us playing twice during the same midweek.
All a big IF though.